WO2003010760A1 - Read/write head assembly - Google Patents

Read/write head assembly Download PDF

Info

Publication number
WO2003010760A1
WO2003010760A1 PCT/GB2002/003366 GB0203366W WO03010760A1 WO 2003010760 A1 WO2003010760 A1 WO 2003010760A1 GB 0203366 W GB0203366 W GB 0203366W WO 03010760 A1 WO03010760 A1 WO 03010760A1
Authority
WO
WIPO (PCT)
Prior art keywords
write
shield
magnetic
gap
magnetic pole
Prior art date
Application number
PCT/GB2002/003366
Other languages
French (fr)
Inventor
Robert Glenn Biskeborn
Original Assignee
International Business Machines Corporation
Ibm United Kingdom Limited
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by International Business Machines Corporation, Ibm United Kingdom Limited filed Critical International Business Machines Corporation
Priority to DE60224539T priority Critical patent/DE60224539T2/en
Priority to JP2003516052A priority patent/JP3999737B2/en
Priority to EP02745669A priority patent/EP1410384B1/en
Priority to KR1020037016794A priority patent/KR100655826B1/en
Publication of WO2003010760A1 publication Critical patent/WO2003010760A1/en

Links

Classifications

    • GPHYSICS
    • G11INFORMATION STORAGE
    • G11BINFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/10Structure or manufacture of housings or shields for heads
    • G11B5/11Shielding of head against electric or magnetic fields
    • GPHYSICS
    • G11INFORMATION STORAGE
    • G11BINFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/127Structure or manufacture of heads, e.g. inductive
    • G11B5/33Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only
    • G11B5/39Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only using magneto-resistive devices or effects
    • G11B5/3903Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only using magneto-resistive devices or effects using magnetic thin film layers or their effects, the films being part of integrated structures
    • G11B5/3967Composite structural arrangements of transducers, e.g. inductive write and magnetoresistive read
    • GPHYSICS
    • G11INFORMATION STORAGE
    • G11BINFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/127Structure or manufacture of heads, e.g. inductive
    • G11B5/31Structure or manufacture of heads, e.g. inductive using thin films
    • G11B5/3103Structure or manufacture of integrated heads or heads mechanically assembled and electrically connected to a support or housing
    • G11B5/3106Structure or manufacture of integrated heads or heads mechanically assembled and electrically connected to a support or housing where the integrated or assembled structure comprises means for conditioning against physical detrimental influence, e.g. wear, contamination
    • GPHYSICS
    • G11INFORMATION STORAGE
    • G11BINFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/40Protective measures on heads, e.g. against excessive temperature 
    • GPHYSICS
    • G11INFORMATION STORAGE
    • G11BINFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/127Structure or manufacture of heads, e.g. inductive
    • G11B5/187Structure or manufacture of the surface of the head in physical contact with, or immediately adjacent to the recording medium; Pole pieces; Gap features
    • G11B5/255Structure or manufacture of the surface of the head in physical contact with, or immediately adjacent to the recording medium; Pole pieces; Gap features comprising means for protection against wear
    • GPHYSICS
    • G11INFORMATION STORAGE
    • G11BINFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/48Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed
    • G11B5/488Disposition of heads
    • G11B5/4893Disposition of heads relative to moving tape

Definitions

  • This invention relates generally to read/write head arrays for magnetic data stores and more particularly to a read/write shield-pairing technique for optimizing head surface wear.
  • the improvement in magnetic medium data storage capacity arises in large part from improvements in the magnetic head assembly used for reading and writing data on the magnetic storage medium.
  • a major improvement in transducer technology arrived with the magnetoresistive (MR) sensor originally developed by the IBM corporation.
  • the MR sensor transduces magnetic field changes in a MR stripe to resistance changes, which are processed to provide digital signals .
  • Data storage density can be increased because a MR sensor offers signal levels higher than those available from conventional inductive read heads for a given bit area.
  • the MR sensor output signal depends only on the instantaneous magnetic field intensity in the storage medium and is independent of the magnetic field time-rate-of-change arising from relative sensor/medium velocity.
  • the quantity of data stored on a magnetic tape may be increased by increasing the number of data tracks on the tape, which also decreases the distance between adjacent tracks and forces adjacent read/write heads closer together. More tracks are made possible by reducing feature sizes of the read and write elements, such as by using thin-film fabrication techniques and MR sensors.
  • the magnetic storage medium such as tape or a magnetic disk surface
  • the magnetic read/write (R/ ) head assembly is passed over the magnetic read/write (R/ ) head assembly for reading data therefrom and writing data thereto.
  • R/ magnetic read/write
  • a read-while-write head assembly includes, for each of one or more data tracks, a write element in-line with a read element, herein denominated a R/W track-pair, wherein the gap of the read element is closely-disposed to and aligned with the gap of the write element, with the read element positioned downstream of the write element in the direction of medium motion.
  • the recovered data is compared to the original data to afford opportunity for action, such as re-recording, to correct errors.
  • the R/W track-pairs are interleaved to form two-rows of alternating read and write elements. Alternate columns (track-pairs) are thereby disposed to read-after-write in alternate directions of tape medium motion.
  • Tape heads suitable for reading and writing on high-density tapes also require precise alignment of the track-pair elements in the head assembly.
  • Practitioners in the art provide very hard wear-resistant layers on the air bearing surfaces of magnetic heads to inhibit wear, for example, a sputtered layer of diamond-like carbon or titanium-carbide, but such layers are also very thin, being perhaps 20 nanometers thick.
  • a magnetic head assembly having an air bearing surface (ABS) , comprising: a read head including: a magnetoresistive (MR) sensor element having opposite ends each connected to a respective electrical lead conductor, the MR sensor element and the two electrical lead conductors being disposed in spaced relationship between two MR element shields; and a first electrical conductor coupling at least one of the MR element shields and at least one of the electrical lead conductors; a write head including: two magnetic pole pieces each having a pole tip portion disposed adjacent the ABS; and a write gap located between the pole tip portions; and a second electrical conductor coupling the one MR element shield and one of the write-gap poles.
  • ABS air bearing surface
  • the write gap is conventionally non-magnetic.
  • the invention further provides a magnetic tape drive including at least one magnetic head assembly as described above, the magnetic tape drive further comprising: a magnetic recording • medium having a recording surface; a motor for moving the magnetic recording medium; a head-mount assembly for supporting the magnetic head assembly with respect to the magnetic recording medium; a second electrical conductor coupling the one MR element shield and one of the write-gap poles.
  • the two spaced magnetic pole tips are disposed in spaced relationship with a write-gap shield such that the one magnetic pole tip is disposed between the write-gap shield and the other magnetic pole tip.
  • the write-gap shield is magnetically and conductively integral with the one magnetic pole tip.
  • the electrical conductors consist essentially of one or more materials chosen from the group of tantalum, copper and gold.
  • the second conductor has a resistence in the range from about 5 kilohms to about 100 kilohms.
  • a wear-resistant interleaved read/write head assembly is preferably provided with improved symmetric wear characteristics.
  • the read/write head assembly employs independent read/write shield-paring and charge-clamped magnetoresistive sensors.
  • head wear is optimised by equalizing the voltage environments of the read and write heads to reduce electrochemical/mechanical erosion of the wear-resistant air bearing surface (ABS) layer.
  • ABS wear-resistant air bearing surface
  • This is in a preferred embodiment accomplished by adding an electrical connection between adjacent electrically conductive reader shields and writer poles/shields.
  • such connection is preferably provided independently for each pair of read/write elements in the array.
  • a write-gap pole or shield is provided adjacent the read gap shield.
  • at least one and preferably both read gap shields is electrically-clamped to one of the MR signal leads (preferably the lead having the most positive potential) or to both MR leads via a center-tapped resister clamping structure that may be appreciated with reference to the commonly-assigned U.S. Patent No. 6,246,553.
  • a write-gap pole or shield of the type used by IBM Corporation for head manufacturability can according to the preferred embodiment be easily connected by a conductor to the adjacent read-gap shield.
  • the invention further provides a method for making a magnetic head assembly that has an air bearing surface (ABS) , comprising the unordered steps of:
  • MR magnetoresistive
  • the method further comprises : (b.3) forming a write-gap shield in spaced relationship with the two spaced magnetic pole tips such that the one magnetic pole tip is disposed between the write-gap shield and the other magnetic pole tip.
  • a magnetic head assembly including a write gap formed between two spaced magnetic pole tips and a magnetoresistive (MR) sensor element having opposite ends each connected to a respective electrical lead conductor, the MR sensor element and the two. electrical lead conductors being disposed in spaced relationship between two MR element shields, wherein the improvement comprises: a first electrical conductor coupling at least one of the MR element shields and at least one of the electrical lead conductors; and a second electrical conductor coupling the one MR element shield and one of the write-gap poles .
  • MR magnetoresistive
  • Fig. 1 illustrates a front view of the air bearing surface (ABS) of an interleaved magnetoresistive (MR) head assembly in relation to a magnetic tape storage medium in accordance with an embodiment of the present invention
  • Fig. 2 illustrates a cutaway portion of the MR head assembly from
  • Fig. 1 expanded to illustrate the features of the interleaved thin-film read and write gap shield-couplings in accordance with an embodiment of the present invention
  • Fig. 3 illustrates a cross-sectional view of the MR head assembly from Fig. 2 taken along 3-3 with insulation between the layers removed in accordance with an embodiment of the present invention
  • Figs. 4A-4B illustrate expanded views of alternative exemplary embodiments of the thin-film read gap of this invention showing the MR shield charge-clamping layer;
  • Fig. 5 illustrates a schematic diagram of a magnetic tape drive useful with the magnetic head assembly of an embodiment of the present invention.
  • Fig. 6 is a block diagram illustrating a preferred embodiment of the method of the present invention for fabricating a magnetic head assembly.
  • Fig. 1 shows the air bearing surface (ABS) of a preferred embodiment an interleaved magnetoresistive (MR) head assembly 10, where the read elements are marked R and the write elements are marked W.
  • the write elements, exemplified by the write head 12 and the read elements, exemplified by the read head 14, are disposed in alternating fashion to form a single set of thirty-eight (for example) read/write track-pairs, exemplified by the R/W track-pair 12-14.
  • the term alternating is intended to include other formats. For example, one format provides that the odd-numbered heads HI, H3, H5 etc. are operative during forward tape movement, while the even-numbered heads H2, H4, H6 etc. are operative during the opposite direction of tape movement.
  • the length of the magnetic tape medium 16 moves in either a forward or reverse direction as indicated by the arrows 18 and 20.
  • Head assembly 10 is shown in Fig. 1 as if magnetic tape medium 16 were transparent, although such tape medium normally is not transparent.
  • Arrow 18 designates a forward movement of tape medium 16
  • arrow 20 designates a reverse direction.
  • Magnetic tape medium 16 and interleaved MR head assembly 10 operate in a transducing relationship in the manner well-known in the art. Other formats usable in the practice of this invention are considered to be within the teaching of this invention.
  • Each of the head elements in head assembly 10 is intended to operate over a plurality of data tracks in magnetic tape medium 16, as may be appreciated with reference to the data tracks TI, T9, T17, etc. in Fig. 1, which shows an exemplary 288-track scheme having a data track density on magnetic tape medium 16 of eight times the recording element density of R/W track-pairs HI, H2, . . . H36 in MR head assembly 10.
  • Tracks T9, T25, . . . T281 may be written with one pass of magnetic tape medium 16 in direction 18 over even-numbered R/w track-pairs H2, H4, . . . H36 and then tracks TI, T17, . . .
  • T273 written on a return pass of magnetic tape medium 16 over the odd-numbered R/W track-pairs HI, H3, . . . H35 by moving the lateral position of MR head assembly 10 in the direction of the arrow 21 by a distance equivalent to one track pitch (T1-T2) , which is about 12% of the R/W track-pair spacing (H1-H2) .
  • Interleaved MR head assembly 10 includes two thin-film modules 22 and 24 of generally identical construction. Modules 22 and 24 are joined together with adhesive layer 25 to form a single physical unit, wherein the R/W track-pairs HI, H2, . . . H36 are aligned as precisely as possible in the direction of tape medium movement. Each module 22, 24 includes one head-gap line 26, 28, respectively, where the individual R/W gaps, exemplified by write head 12 and read head 14, in each module are precisely located. Each thin-film module 22, 24 includes a separate substrate 30, 32 and a separate closure piece 34, 36, respectively.
  • Substrate 30 is bonded near head-gap line 26 by adhesive to closure piece 34 to form thin-film module 22 and substrate 32 is bonded near head-gap line 28 by adhesive to closure piece 36 to form thin-film module 24.
  • An underlayer (35, 37) may be deposited on the substrate (30, 32) before formation of the R/W heads and an overlayer (39, 41) is deposited over the R/W heads before placement of the closure piece (34, 36) , substantially as shown.
  • head-gap lines 26, 28 are disposed perpendicular to the directions of tape medium movement as represented by arrows 18, 20.
  • the R/W head-gaps at H1-H36 in thin-film module 22 cooperate with the corresponding R/w head-gaps in thin-film module 24 to provide read-after- rite functionality during movement of magnetic tape medium 16.
  • the read head gaps of one thin-film module are precisely aligned with the write head gaps of the other module along the direction of movement of tape medium 16.
  • write head 12 is aligned with read head 14 to form a single R/W track-pair HI for read-after-write during magnetic tape movement in the direction indicated by arrow 18.
  • Fig. 2 shows in detail and in accordance with the preferred embodiment of the present invention a portion of substrate 30 from Fig. 1, including portions of three exemplary R/W head gaps on head-gap line 26, which are aligned with track-pairs H3-H5 substantially as shown.
  • the thin-film elements shown in Fig. 2 are illustrated showing submicron detail in the usual manner and are not to scale.
  • a magnetoresistive (MR) sensor element 40 is disposed between the two MR element (S2 & SI) shields 46 and 48, with each MR sensor end coupled to an electrical lead conductor 42 and 4 .
  • the relative disposition of electrical lead conductors 42-44 may be better appreciated with reference to Fig. 3, which illustrates a semi-transparent cross ⁇ -sectional view of substrate 30 from Fig. 2 taken along section line 3-3.
  • read head 38 is seen to be disposed between the two write heads 50 and 52 positioned for writing data on track-pairs H3, H5, each adjacent to track-pair H4, substantially as shown.
  • Write head 52 is substantially identical to write head 50, which includes a write-gap 54 defined by two spaced magnetic pole (PI & P2) tips 56 and 58.
  • Write head 50 may also include a write-gap SI shield 60 (substantially identical to the write-gap SI shield 62 in write head 52) positioned on and integral with magnetic pole PI tip 56 and substantially in line with MR element SI shield 48.
  • Write-gap SI shield 60 may be electrically isolated from magnetic pole PI tip 56 by means of an intermediate insulating layer (not shown) but is preferably integral therewith and is deposited using the same material and deposition cycle as MR element SI shield 48 to improve manufacturability.
  • magnetic tape medium 16 is illustrated in cross-section and shown adjacent the air bearing surface (ABS) 64 of substrate 30 and interleaved MR head assembly 10 (Fig. 1) .
  • the direction of motion of magnetic tape medium 16 is perpendicular to the page, as indicated -by the oncoming and retreating arrow symbols.
  • Fig. 3 shows in semi-transparent cross-section the relative planar view of some elements of interest, particularly the back-gap portion 66 of magnetic pole Pi piece 56 where it is joined to the back gap portion of the other magnetic pole P2 piece 58 (see Fig. 2) to complete the magnetic circuit energized by the write-coil 68 in the usual manner.
  • FIGs. 1 shows in semi-transparent cross-section the relative planar view of some elements of interest, particularly the back-gap portion 66 of magnetic pole Pi piece 56 where it is joined to the back gap portion of the other magnetic pole P2 piece 58 (see Fig. 2) to complete the magnetic circuit energized by the write-coil 68 in the usual manner.
  • an electrical connection 70 is established between the electrically-conductive MR element SI shield 48 and the immediately-adjacent write-gap SI shield 60 (and thereby to magnetic pole PI piece 56) .
  • Electrical connection 70 is established for each laterally-adjacent R/W head pair along head-gap lines 26 and 28 (Fig. 1) and is implemented in Fig. 2 by the electrical conductor 70, which is merely one of many useful means for conductively coupling the two shield elements 48 and 60.
  • the electrical connection exemplified by electrical conductor 70 is made independently for each reader-writer pair along both head-gap lines 26 and 28 of substrates 30 and 32 (Fig. 1) . Electrical conductor 70 (Figs.
  • electrical conductor 70 operates to couple MR element SI shield 48 to both write-gap SI shield 60 and magnetic pole PI tip 56, in accordance with a preferred embodiment of the invention.
  • Electrical conductor 70 may, for example, have a resistance in the range from about 5 kilohms to about 50 kilohms or more.
  • MR element shield 48 is also connected by means of an electrical conductor 72 to one of electrical lead conductors 42-44, preferably the most positively-biased of the two (shown as electrical lead conductor 44 in Fig. 3) .
  • Figs. 2-3 show this connection between MR element shield 48 and electrical lead conductor 44, for example.
  • Figs. 4A and 4B illustrate this charge-clamping connection in the alternative.
  • Fig. 4A shows MR element shield 48a clamped to. electrical lead conductor 44a by means of the electrical conductor 72a.
  • MR element shield 48b is connected through the electrical conductor 72b to electrical lead conductor 42b.
  • the fabrication and operation of electrical conductor 72a-b may be better appreciated with reference to the commonly-assigned U.S. Patent No. 6,246,553.
  • Sputtered alumina is known to be less wear-resistant in acidic and basic environments, such as in conjunction with the head-tape interface at ABS 64, than in neutral environments.
  • the inventor has shown that this conjectured chemical-mechanical mechanism appears to be influenced by the local electrical environment, which is controlled in the interleaved MR head assembly by equalizing the robustness of the write heads and the read heads .
  • Fig. 5 shows a schematic diagram of a magnetic tape drive 73 useful with magnetic head assembly 10 discussed above in connection with Figs . 1-4.
  • the controller 74 accepts information from a supply reel tachometer 76, which is coupled to a supply reel motor 78, which is controlled by controller 74 to reversibly rotate a supply reel 82 shown within a single supply reel cartridge 83.
  • a take-up reel tachometer 84 is connected to a take-up reel motor 86 that is reversibly driven by controller 74. Take-up reel motor 86 drives a take-up reel 88.
  • Magnetic tape 16 and its leader block moves along a path shown by the dotted line 90, from supply reel 82 past an idler bearing 92, the air bearing tape guides 94 and 96, continuing around a roller 98 coupled to a tension arm transducer 100 under the control of controller 74, and therefrom to take-up reel 88, substantially as shown.
  • the resulting output from the read elements in MR head assembly 10 is transmitted to controller 74, which also directs data from an .external source to head assembly 10 for transfer onto tape medium 16 through the plurality of write elements in MR head assembly 10.
  • Magnetic tape drive 73 may be generally of the one-half inch type having a single reel cartridge. As is well-known in the tape drive industry, other media formats are also available for example, quarter-inch cartridge (QIC), digital linear tape (D T) , digital analog tape (DAT), and the like.
  • interleaved MR head assembly 10 is primarily suitable for data tape recording applications, the same fabrication principles could be applied to making a magnetic R/W head assembly for other magnetic recording applications.
  • Disk drive applications generally use merged or piggy-back R/w heads that are less troubled with head wear problems and unlikely to need the improvement disclosed herein.
  • Fig. 6 provides a block diagram illustrating a preferred method for fabricating a magnetic head assembly in accordance with the MR head assembly method of an embodiment of the present invention.
  • the diagram in Fig. 6 is shown in sections, with the left column showing steps for forming the write element plurality, the right column showing steps for forming the read element plurality, and the middle column showing steps common to both. In practice, these processes are performed concurrently so that both read and write elements are formed as much as possible in the same process steps . The following exemplary- description is limited to a single adjacent write-read pair, from which the process may be easily appreciated.
  • the first step 134 prepares the surface of wafer substrate 30 (Fig. 1) .
  • the insulating alumina undercoat layer 35 (Fig. 1) is sputtered onto the surface of substrate 30.
  • the surface of alumina undercoat layer 35 is lapped to a thickness of 3-4 microns. This provides a flat surface for deposition of the first Sendust SI layer at the step 140, which is patterned to create MR element SI shield 48 at the step 142 and write-gap SI shield 60 at the step 144 (Figs. 2-3) .
  • electrical conductor 70 is formed to couple upper SI MR shield 48 to upper SI write shield 60.
  • the several layers making up the MR sensor including MR sensor element 40, electrical lead conductors 42 and 44 and the embracing insulating layers, are deposited and etched in the step 148.
  • an insulating layer may be deposited over upper SI write shield 60 to isolate it from magnetic pole PI tip 56, but optional step 150 is preferably omitted so that the S2 layer deposition in the step 152 is made directly over upper SI write shield 60 to join it to magnetic pole PI tip 56, which is patterned in the step 154.
  • the step 156 patterns MR element S2 shield 46.
  • the step 158 deposits write-coil 68 in the usual manner (Fig. 3) and the step 160 deposits magnetic pole P2 tip 58.

Abstract

A magnetic head assembly with an air bearing surface (ABS) layer over a double-shielded magnetoresistive (MR) sensor and a write gap formed between two spaced magnetic pole tips (P1, P2), with an optional write-gap shield (S1) disposed so that one magnetic pole tip is disposed between the write-gap shield and the other magnetic pole tip. At least one of the MR element shields (S1) is electrically connected to one of the MR signal lead conductors (44) (preferably the one having the most positive potential) and the one magnetic pole tip (and/or the optional write-gap shield) is coupled to the clamped MR element shield (48) with an electrical conductor (70). For multi-track read/write arrays, the connection between adjacent reader shield and writer pole and/or shield is provided independently for each read/write pair in the array, thereby equalizing the voltage environments to reduce variations in the chemical/mechanical erosion of the read and write head ABS layers.

Description

READ/WRITE HEAD ASSEMBLY
BACKGROUND OF THE INVENTION
Field of the Invention:
This invention relates generally to read/write head arrays for magnetic data stores and more particularly to a read/write shield-pairing technique for optimizing head surface wear.
Description of the Prior Art
Business, science and entertainment applications depend upon computers to process and record data, often with large volumes of the data being stored or transferred to nonvolatile storage media, such as magnetic discs, magnetic tape cartridges, optical disk cartridges, floppy diskettes, or floptical diskettes. Typically, magnetic tape is the most economical means of storing or archiving the data. Storage technology is continually pushed to increase storage capacity and storage reliability. Improvement in data storage densities in magnetic storage media, for example, has resulted from improved medium materials, improved error correction techniques and decreased areal bit sizes. The data capacity of half-inch magnetic tape, for example, is now measured in tens of gigabytes on 256 data tracks.
The improvement in magnetic medium data storage capacity arises in large part from improvements in the magnetic head assembly used for reading and writing data on the magnetic storage medium. A major improvement in transducer technology arrived with the magnetoresistive (MR) sensor originally developed by the IBM corporation. The MR sensor transduces magnetic field changes in a MR stripe to resistance changes, which are processed to provide digital signals . Data storage density can be increased because a MR sensor offers signal levels higher than those available from conventional inductive read heads for a given bit area. Moreover, the MR sensor output signal depends only on the instantaneous magnetic field intensity in the storage medium and is independent of the magnetic field time-rate-of-change arising from relative sensor/medium velocity.
The quantity of data stored on a magnetic tape may be increased by increasing the number of data tracks on the tape, which also decreases the distance between adjacent tracks and forces adjacent read/write heads closer together. More tracks are made possible by reducing feature sizes of the read and write elements, such as by using thin-film fabrication techniques and MR sensors. In operation the magnetic storage medium, such as tape or a magnetic disk surface, is passed over the magnetic read/write (R/ ) head assembly for reading data therefrom and writing data thereto. In modern magnetic tape recorders adapted for computer data storage, read-while-write capability with MR sensors is an essential feature for providing fully recoverable magnetically stored data. The interleaved R/W magnetic tape head with MR sensors allows increased track density on the tape medium while providing bi-directional read-while-write operation of the tape medium to give immediate read back verification of data just written onto the tape medium. A read-while-write head assembly includes, for each of one or more data tracks, a write element in-line with a read element, herein denominated a R/W track-pair, wherein the gap of the read element is closely-disposed to and aligned with the gap of the write element, with the read element positioned downstream of the write element in the direction of medium motion. By continually reading just recorded data, the quality of the recorded data is immediately verified while the original data is still available in temporary storage in the recording system. The recovered data is compared to the original data to afford opportunity for action, such as re-recording, to correct errors. In the interleaved head, the R/W track-pairs are interleaved to form two-rows of alternating read and write elements. Alternate columns (track-pairs) are thereby disposed to read-after-write in alternate directions of tape medium motion. Tape heads suitable for reading and writing on high-density tapes also require precise alignment of the track-pair elements in the head assembly.
Tape heads in particular suffer from head wear caused by motion of the magnetic recording tape. Repeated passes of the tape medium over the wear-resistant tape head surface may eventually wear away some of the surface, which can impair head performance. This may be a particular problem for thin-film magnetic heads where the thin-film layer structure may see relatively considerable wear with brief operation, giving an unacceptably short lifetime for the magnetic head assembly. Practitioners in the art provide very hard wear-resistant layers on the air bearing surfaces of magnetic heads to inhibit wear, for example, a sputtered layer of diamond-like carbon or titanium-carbide, but such layers are also very thin, being perhaps 20 nanometers thick. While wear mechanisms are not perfectly understood in the art, one problem is believed to arise from accelerated wear in line with the write gap, which is disadvantageous for head-assembly life-expectancy. The wear difference is media-dependent and can be severe enough to make certain media incompatible with such head assemblies.
SUMMARY OF THE INVENTION
Accordingly the invention provides a magnetic head assembly having an air bearing surface (ABS) , comprising: a read head including: a magnetoresistive (MR) sensor element having opposite ends each connected to a respective electrical lead conductor, the MR sensor element and the two electrical lead conductors being disposed in spaced relationship between two MR element shields; and a first electrical conductor coupling at least one of the MR element shields and at least one of the electrical lead conductors; a write head including: two magnetic pole pieces each having a pole tip portion disposed adjacent the ABS; and a write gap located between the pole tip portions; and a second electrical conductor coupling the one MR element shield and one of the write-gap poles.
The write gap is conventionally non-magnetic.
According to one aspect, the invention further provides a magnetic tape drive including at least one magnetic head assembly as described above, the magnetic tape drive further comprising: a magnetic recording medium having a recording surface; a motor for moving the magnetic recording medium; a head-mount assembly for supporting the magnetic head assembly with respect to the magnetic recording medium; a second electrical conductor coupling the one MR element shield and one of the write-gap poles.
Preferably the two spaced magnetic pole tips are disposed in spaced relationship with a write-gap shield such that the one magnetic pole tip is disposed between the write-gap shield and the other magnetic pole tip.
Preferably the write-gap shield is magnetically and conductively integral with the one magnetic pole tip.
In a preferred embodiment the electrical conductors consist essentially of one or more materials chosen from the group of tantalum, copper and gold. In a preferred embodiment, the second conductor has a resistence in the range from about 5 kilohms to about 100 kilohms.
A wear-resistant interleaved read/write head assembly is preferably provided with improved symmetric wear characteristics.
Preferably the read/write head assembly employs independent read/write shield-paring and charge-clamped magnetoresistive sensors.
Preferably head wear is optimised by equalizing the voltage environments of the read and write heads to reduce electrochemical/mechanical erosion of the wear-resistant air bearing surface (ABS) layer. This is in a preferred embodiment accomplished by adding an electrical connection between adjacent electrically conductive reader shields and writer poles/shields. For thin-film multi-track read/write arrays, such connection is preferably provided independently for each pair of read/write elements in the array.
In a preferred embodiment a write-gap pole or shield is provided adjacent the read gap shield. In a preferred embodiment at least one and preferably both read gap shields is electrically-clamped to one of the MR signal leads (preferably the lead having the most positive potential) or to both MR leads via a center-tapped resister clamping structure that may be appreciated with reference to the commonly-assigned U.S. Patent No. 6,246,553.
It is an advantage of this invention that a write-gap pole or shield of the type used by IBM Corporation for head manufacturability can according to the preferred embodiment be easily connected by a conductor to the adjacent read-gap shield.
The invention further provides a method for making a magnetic head assembly that has an air bearing surface (ABS) , comprising the unordered steps of:
(a) making a read head including the steps of:
(a.l) forming a magnetoresistive (MR) sensor element having two ends disposed adjacent the ABS in spaced relationship between two MR element shields; (a.2) forming an electrical lead conductor coupled to each MR sensor element end; and
(a.3) forming a first electrical conductor coupling at least one of the MR element shields and at least one of the electrical lead conductors;
(b) making a write head including the steps of:
(b.l) forming two magnetic pole pieces each having a pole tip portion disposed adjacent the ABS;
(b.2) forming a nonmagnetic write gap located between the pole tip portions; and
(c) forming a second electrical conductor coupling the one MR element shield and one of the write-gap poles .
Preferably the method further comprises : (b.3) forming a write-gap shield in spaced relationship with the two spaced magnetic pole tips such that the one magnetic pole tip is disposed between the write-gap shield and the other magnetic pole tip.
According to one embodiment, there is provided a magnetic head assembly including a write gap formed between two spaced magnetic pole tips and a magnetoresistive (MR) sensor element having opposite ends each connected to a respective electrical lead conductor, the MR sensor element and the two. electrical lead conductors being disposed in spaced relationship between two MR element shields, wherein the improvement comprises: a first electrical conductor coupling at least one of the MR element shields and at least one of the electrical lead conductors; and a second electrical conductor coupling the one MR element shield and one of the write-gap poles .
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of the present invention will now be described, by way of example only, and with reference to the present invention. It should be noted that like reference numerals represent like features throughout the figures: Fig. 1 illustrates a front view of the air bearing surface (ABS) of an interleaved magnetoresistive (MR) head assembly in relation to a magnetic tape storage medium in accordance with an embodiment of the present invention; Fig. 2 illustrates a cutaway portion of the MR head assembly from
Fig. 1 expanded to illustrate the features of the interleaved thin-film read and write gap shield-couplings in accordance with an embodiment of the present invention;
Fig. 3 illustrates a cross-sectional view of the MR head assembly from Fig. 2 taken along 3-3 with insulation between the layers removed in accordance with an embodiment of the present invention;
Figs. 4A-4B illustrate expanded views of alternative exemplary embodiments of the thin-film read gap of this invention showing the MR shield charge-clamping layer;
Fig. 5 illustrates a schematic diagram of a magnetic tape drive useful with the magnetic head assembly of an embodiment of the present invention; and
Fig. 6 is a block diagram illustrating a preferred embodiment of the method of the present invention for fabricating a magnetic head assembly.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Fig. 1 shows the air bearing surface (ABS) of a preferred embodiment an interleaved magnetoresistive (MR) head assembly 10, where the read elements are marked R and the write elements are marked W. The write elements, exemplified by the write head 12 and the read elements, exemplified by the read head 14, are disposed in alternating fashion to form a single set of thirty-eight (for example) read/write track-pairs, exemplified by the R/W track-pair 12-14. As used herein, the term alternating is intended to include other formats. For example, one format provides that the odd-numbered heads HI, H3, H5 etc. are operative during forward tape movement, while the even-numbered heads H2, H4, H6 etc. are operative during the opposite direction of tape movement.
Generally, the length of the magnetic tape medium 16 moves in either a forward or reverse direction as indicated by the arrows 18 and 20. Head assembly 10 is shown in Fig. 1 as if magnetic tape medium 16 were transparent, although such tape medium normally is not transparent. Arrow 18 designates a forward movement of tape medium 16 and arrow 20 designates a reverse direction. Magnetic tape medium 16 and interleaved MR head assembly 10 operate in a transducing relationship in the manner well-known in the art. Other formats usable in the practice of this invention are considered to be within the teaching of this invention.
Each of the head elements in head assembly 10 is intended to operate over a plurality of data tracks in magnetic tape medium 16, as may be appreciated with reference to the data tracks TI, T9, T17, etc. in Fig. 1, which shows an exemplary 288-track scheme having a data track density on magnetic tape medium 16 of eight times the recording element density of R/W track-pairs HI, H2, . . . H36 in MR head assembly 10. Tracks T9, T25, . . . T281 may be written with one pass of magnetic tape medium 16 in direction 18 over even-numbered R/w track-pairs H2, H4, . . . H36 and then tracks TI, T17, . . . T273 written on a return pass of magnetic tape medium 16 over the odd-numbered R/W track-pairs HI, H3, . . . H35 by moving the lateral position of MR head assembly 10 in the direction of the arrow 21 by a distance equivalent to one track pitch (T1-T2) , which is about 12% of the R/W track-pair spacing (H1-H2) .
Interleaved MR head assembly 10 includes two thin-film modules 22 and 24 of generally identical construction. Modules 22 and 24 are joined together with adhesive layer 25 to form a single physical unit, wherein the R/W track-pairs HI, H2, . . . H36 are aligned as precisely as possible in the direction of tape medium movement. Each module 22, 24 includes one head-gap line 26, 28, respectively, where the individual R/W gaps, exemplified by write head 12 and read head 14, in each module are precisely located. Each thin-film module 22, 24 includes a separate substrate 30, 32 and a separate closure piece 34, 36, respectively. Substrate 30 is bonded near head-gap line 26 by adhesive to closure piece 34 to form thin-film module 22 and substrate 32 is bonded near head-gap line 28 by adhesive to closure piece 36 to form thin-film module 24. An underlayer (35, 37) may be deposited on the substrate (30, 32) before formation of the R/W heads and an overlayer (39, 41) is deposited over the R/W heads before placement of the closure piece (34, 36) , substantially as shown. As precisely as possible, head-gap lines 26, 28 are disposed perpendicular to the directions of tape medium movement as represented by arrows 18, 20. The R/W head-gaps at H1-H36 in thin-film module 22 cooperate with the corresponding R/w head-gaps in thin-film module 24 to provide read-after- rite functionality during movement of magnetic tape medium 16. The read head gaps of one thin-film module are precisely aligned with the write head gaps of the other module along the direction of movement of tape medium 16. Thus, for example, write head 12 is aligned with read head 14 to form a single R/W track-pair HI for read-after-write during magnetic tape movement in the direction indicated by arrow 18.
Fig. 2 shows in detail and in accordance with the preferred embodiment of the present invention a portion of substrate 30 from Fig. 1, including portions of three exemplary R/W head gaps on head-gap line 26, which are aligned with track-pairs H3-H5 substantially as shown. The thin-film elements shown in Fig. 2 are illustrated showing submicron detail in the usual manner and are not to scale. Considering first the read-head 38 at track-pair H4, a magnetoresistive (MR) sensor element 40 is disposed between the two MR element (S2 & SI) shields 46 and 48, with each MR sensor end coupled to an electrical lead conductor 42 and 4 . The relative disposition of electrical lead conductors 42-44 may be better appreciated with reference to Fig. 3, which illustrates a semi-transparent cross^-sectional view of substrate 30 from Fig. 2 taken along section line 3-3.
In Fig. 2 (not to scale) , read head 38 is seen to be disposed between the two write heads 50 and 52 positioned for writing data on track-pairs H3, H5, each adjacent to track-pair H4, substantially as shown. Write head 52 is substantially identical to write head 50, which includes a write-gap 54 defined by two spaced magnetic pole (PI & P2) tips 56 and 58. Write head 50 may also include a write-gap SI shield 60 (substantially identical to the write-gap SI shield 62 in write head 52) positioned on and integral with magnetic pole PI tip 56 and substantially in line with MR element SI shield 48. Write-gap SI shield 60 may be electrically isolated from magnetic pole PI tip 56 by means of an intermediate insulating layer (not shown) but is preferably integral therewith and is deposited using the same material and deposition cycle as MR element SI shield 48 to improve manufacturability.
Referring also to Fig. 3, magnetic tape medium 16 is illustrated in cross-section and shown adjacent the air bearing surface (ABS) 64 of substrate 30 and interleaved MR head assembly 10 (Fig. 1) . The direction of motion of magnetic tape medium 16 is perpendicular to the page, as indicated -by the oncoming and retreating arrow symbols. Fig. 3 shows in semi-transparent cross-section the relative planar view of some elements of interest, particularly the back-gap portion 66 of magnetic pole Pi piece 56 where it is joined to the back gap portion of the other magnetic pole P2 piece 58 (see Fig. 2) to complete the magnetic circuit energized by the write-coil 68 in the usual manner. In accordance with the preferred embodiment, as schematically illustrated in Figs. 2-3, an electrical connection 70 is established between the electrically-conductive MR element SI shield 48 and the immediately-adjacent write-gap SI shield 60 (and thereby to magnetic pole PI piece 56) . Electrical connection 70 is established for each laterally-adjacent R/W head pair along head-gap lines 26 and 28 (Fig. 1) and is implemented in Fig. 2 by the electrical conductor 70, which is merely one of many useful means for conductively coupling the two shield elements 48 and 60. In accordance with the preferred embodiment, the electrical connection exemplified by electrical conductor 70 is made independently for each reader-writer pair along both head-gap lines 26 and 28 of substrates 30 and 32 (Fig. 1) . Electrical conductor 70 (Figs. 2-3) is preferably non-magnetic and may be formed by depositing a layer of conductive metal, such as tantalum, copper or gold, or any other useful material of low to intermediate resistivity. Note that if write-gap SI shield 60 is integral with magnetic pole PI tip 56, then electrical conductor 70 operates to couple MR element SI shield 48 to both write-gap SI shield 60 and magnetic pole PI tip 56, in accordance with a preferred embodiment of the invention. Electrical conductor 70 may, for example, have a resistance in the range from about 5 kilohms to about 50 kilohms or more.
According to the preferred embodiment, within each read head, which is exemplified by read head 38, MR element shield 48 is also connected by means of an electrical conductor 72 to one of electrical lead conductors 42-44, preferably the most positively-biased of the two (shown as electrical lead conductor 44 in Fig. 3) . Figs. 2-3 show this connection between MR element shield 48 and electrical lead conductor 44, for example. Figs. 4A and 4B illustrate this charge-clamping connection in the alternative. Fig. 4A shows MR element shield 48a clamped to. electrical lead conductor 44a by means of the electrical conductor 72a. Similarly, according to Fig. 4B, MR element shield 48b is connected through the electrical conductor 72b to electrical lead conductor 42b. The fabrication and operation of electrical conductor 72a-b may be better appreciated with reference to the commonly-assigned U.S. Patent No. 6,246,553.
In operation, the presence of electrical conductor 70 and electrical conductor 72 clamps the electrical potential of write-gap shield 60 to that of MR element shield 48, which is clamped to the voltage potential of MR electrical lead conductor 42 (or 44) . This arrangement forces the voltage potentials to be the same for both write and read heads 50 and 38, thereby reducing the differences in wear between the two adjacent R/W heads 38, 50. By equalizing the electrical environment over adjacent heads, the erosion of the wear-resistant alumina surface and other related components is equalized. This occurs because any such wear arising from electrically-enhanced alumina erosion is equalized. Sputtered alumina is known to be less wear-resistant in acidic and basic environments, such as in conjunction with the head-tape interface at ABS 64, than in neutral environments. The inventor has shown that this conjectured chemical-mechanical mechanism appears to be influenced by the local electrical environment, which is controlled in the interleaved MR head assembly by equalizing the robustness of the write heads and the read heads .
Fig. 5 shows a schematic diagram of a magnetic tape drive 73 useful with magnetic head assembly 10 discussed above in connection with Figs . 1-4. The controller 74 accepts information from a supply reel tachometer 76, which is coupled to a supply reel motor 78, which is controlled by controller 74 to reversibly rotate a supply reel 82 shown within a single supply reel cartridge 83. A take-up reel tachometer 84 is connected to a take-up reel motor 86 that is reversibly driven by controller 74. Take-up reel motor 86 drives a take-up reel 88. Magnetic tape 16 and its leader block moves along a path shown by the dotted line 90, from supply reel 82 past an idler bearing 92, the air bearing tape guides 94 and 96, continuing around a roller 98 coupled to a tension arm transducer 100 under the control of controller 74, and therefrom to take-up reel 88, substantially as shown. The resulting output from the read elements in MR head assembly 10 is transmitted to controller 74, which also directs data from an .external source to head assembly 10 for transfer onto tape medium 16 through the plurality of write elements in MR head assembly 10. Magnetic tape drive 73 may be generally of the one-half inch type having a single reel cartridge. As is well-known in the tape drive industry, other media formats are also available for example, quarter-inch cartridge (QIC), digital linear tape (D T) , digital analog tape (DAT), and the like.
While the interleaved MR head assembly 10 is primarily suitable for data tape recording applications, the same fabrication principles could be applied to making a magnetic R/W head assembly for other magnetic recording applications. Disk drive applications generally use merged or piggy-back R/w heads that are less troubled with head wear problems and unlikely to need the improvement disclosed herein.
Fig. 6 provides a block diagram illustrating a preferred method for fabricating a magnetic head assembly in accordance with the MR head assembly method of an embodiment of the present invention. For expository purposes, the diagram in Fig. 6 is shown in sections, with the left column showing steps for forming the write element plurality, the right column showing steps for forming the read element plurality, and the middle column showing steps common to both. In practice, these processes are performed concurrently so that both read and write elements are formed as much as possible in the same process steps . The following exemplary- description is limited to a single adjacent write-read pair, from which the process may be easily appreciated. In forming the plurality of read and write elements, the first step 134 prepares the surface of wafer substrate 30 (Fig. 1) . At the step 136, the insulating alumina undercoat layer 35 (Fig. 1) is sputtered onto the surface of substrate 30. At the step 138, the surface of alumina undercoat layer 35 is lapped to a thickness of 3-4 microns. This provides a flat surface for deposition of the first Sendust SI layer at the step 140, which is patterned to create MR element SI shield 48 at the step 142 and write-gap SI shield 60 at the step 144 (Figs. 2-3) . Thereafter, in the step 146, electrical conductor 70 is formed to couple upper SI MR shield 48 to upper SI write shield 60. The several layers making up the MR sensor, including MR sensor element 40, electrical lead conductors 42 and 44 and the embracing insulating layers, are deposited and etched in the step 148. Optionally, in the step 150, an insulating layer may be deposited over upper SI write shield 60 to isolate it from magnetic pole PI tip 56, but optional step 150 is preferably omitted so that the S2 layer deposition in the step 152 is made directly over upper SI write shield 60 to join it to magnetic pole PI tip 56, which is patterned in the step 154. The step 156 patterns MR element S2 shield 46. The step 158 deposits write-coil 68 in the usual manner (Fig. 3) and the step 160 deposits magnetic pole P2 tip 58. Not shown are the various patterning steps required to complete the magnetic closure in back gap portion 66 between the magnetic pole PI & P2 layers. Also not shown are the steps required to connect at least one and preferably both read gap shields to one of the MR signal leads (preferably the lead having the most positive potential) or to both MR leads via a center-tapped resister clamping structure. This process is fully described in the commonly-assigned U.S. Patent No. 6,246,553. Finally, a covering alumina layer is sputtered in the step 162 and lapped in the step 164 to form overlayer 39 (Fig. 1) .

Claims

1. A magnetic head assembly having an air bearing surface (ABS), comprising:
a read head including:
a magnetoresistive (MR) sensor element having opposite ends each connected to a respective electrical lead conductor, the MR sensor element and the two electrical lead conductors being disposed in spaced relationship between two MR element shields; and
a first electrical conductor coupling at least one of the MR element shields and at least one of the electrical lead conductors;
a write head including:
two magnetic pole pieces each having a pole tip portion disposed adjacent the ABS; and
a write gap located between the pole tip portions; and a second electrical conductor coupling the one MR element shield and one of the write-gap poles.
2.. The assembly of claim 1 wherein the two spaced magnetic pole tips are disposed in spaced relationship with a write-gap shield such that the one magnetic pole tip is disposed between the write-gap shield and the other magnetic pole tip
3. The assembly of claim 2 wherein the write-gap shield is magnetically and conductively integral with the one magnetic pole tip.
4. The assembly of claim 1 wherein the electrical conductors consist essentially of one or more materials chosen from the group of tantalum, copper and gold.
5. The assembly of claim 1 wherein the second conductor has a resistence in the range from about 5 kilohms to about 100 kilohms.
6. A magnetic tape drive including at least one magnetic head assembly of claim 1, the magnetic tape drive further comprising: a magnetic recording medium having a recording surface;
a motor for moving the magnetic recording medium;
a head-mount assembly for supporting the magnetic head assembly with respect to the magnetic recording medium;
a second electrical conductor coupling the one MR element shield and one of the write-gap poles .
7. A method for making a magnetic head assembly that has an air bearing surface (ABS) , comprising the unordered steps of:
(a) making a read head including the steps of:
(a.l) forming a magnetoresistive (MR) sensor element having two ends disposed adjacent the ABS in spaced relationship between two MR element shields ,-
(a.2) forming an electrical lead conductor coupled to each MR sensor element end; and
(a.3) forming a first electrical conductor coupling at least one of the MR element shields and at least one of the electrical lead conductors;
(b) making a write head including the steps of:
(b.l) forming two magnetic pole pieces each having a pole tip portion disposed adjacent the ABS;
(b.2) forming a nonmagnetic write gap located between the pole tip portions ; and
(c) forming a second electrical conductor coupling the one MR element shield and one of the write-gap poles.
8. The method of claim 7 further comprising the step of :
(b.3) forming a write-gap shield in spaced relationship with the two spaced magnetic pole tips such that the one magnetic pole tip is disposed between the write-gap shield and the other magnetic pole tip.
PCT/GB2002/003366 2001-07-23 2002-07-22 Read/write head assembly WO2003010760A1 (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
DE60224539T DE60224539T2 (en) 2001-07-23 2002-07-22 READ / WRITE HEAD ARRANGEMENT
JP2003516052A JP3999737B2 (en) 2001-07-23 2002-07-22 Read / write head assembly
EP02745669A EP1410384B1 (en) 2001-07-23 2002-07-22 Read/write head assembly
KR1020037016794A KR100655826B1 (en) 2001-07-23 2002-07-22 Read/write head assembly

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US09/911,555 US6760199B2 (en) 2001-07-23 2001-07-23 Read/write head assembly employing independent read/write shield-pairing and charge-clamped magnetoresistive sensors
US09/911,555 2001-07-23

Publications (1)

Publication Number Publication Date
WO2003010760A1 true WO2003010760A1 (en) 2003-02-06

Family

ID=25430455

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB2002/003366 WO2003010760A1 (en) 2001-07-23 2002-07-22 Read/write head assembly

Country Status (7)

Country Link
US (1) US6760199B2 (en)
EP (1) EP1410384B1 (en)
JP (1) JP3999737B2 (en)
KR (1) KR100655826B1 (en)
AT (1) ATE383642T1 (en)
DE (1) DE60224539T2 (en)
WO (1) WO2003010760A1 (en)

Families Citing this family (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6879471B2 (en) * 2003-06-17 2005-04-12 Seagate Technology Llc Recording head design for identifying reader-to-permanent magnet isolation failure
JP2005032386A (en) * 2003-07-10 2005-02-03 Sony Corp Tape recording system and head device
US7719802B2 (en) * 2003-09-23 2010-05-18 Seagate Technology Llc Magnetic sensor with electrically defined active area dimensions
US8264793B2 (en) * 2004-01-30 2012-09-11 International Business Machines Corporation Tape head with facing beams each having a head chip positioned in a recess thereof
US7251878B2 (en) * 2004-06-30 2007-08-07 Hitachi Global Storage Technologies Netherlands B.V. Method and apparatus for defining leading edge taper of a write pole tip
US7692893B2 (en) * 2004-06-30 2010-04-06 Hitachi Global Storage Technologies Netherlands, B.V. Side-by-side magnetic head configuration with flared pole tip layer and read sensor sharing same plane
US7551393B2 (en) * 2004-08-23 2009-06-23 International Business Machines Corporation Tape recording head with multiple planes of transducer arrays
US7535674B2 (en) 2004-09-09 2009-05-19 Hitachi Global Storage Technologies Netherlands B.V. Narrow pitch tape head array using an orthogonal backgap
US7567409B2 (en) * 2004-09-09 2009-07-28 Hitachi Global Storage Technologies Netherlands B.V. Multilayer narrow pitch tape head array
US7392579B2 (en) * 2005-03-07 2008-07-01 Headway Technologies, Inc. Method for protecting a slider mounted CPP GMR or TMR read head sensor from noise and ESD damage
US7414811B2 (en) * 2005-08-26 2008-08-19 International Business Machines Corporation Magnetic head having three modules
US7660072B2 (en) * 2005-08-26 2010-02-09 International Business Machines Corporation Magnetic head with planar outrigger
US7400474B2 (en) * 2005-10-28 2008-07-15 International Business Machines Corporation Conductive pairing for piggyback magnetic head
US7548397B2 (en) * 2005-11-16 2009-06-16 International Business Machines Corporation Magnetic reader with piggybacked fence
US7486475B2 (en) * 2005-12-14 2009-02-03 International Business Machines Corporation Magnetic data system having bias circuit with bias resistor
US7791834B2 (en) 2006-08-14 2010-09-07 International Business Machines Corporation Magnetic head having a ratio of back gap width to front gap width in about a defined range
US7382569B2 (en) * 2006-10-11 2008-06-03 Intenational Business Machines Corporation Progressive track width head and method
US7480117B2 (en) * 2006-12-12 2009-01-20 International Business Machines Corporation High areal density tape head
US8009386B2 (en) * 2007-11-26 2011-08-30 Tdk Corporation Magnetic tape head with magnetic head layer formed on base substrate
JP4930617B2 (en) * 2010-03-26 2012-05-16 ソニー株式会社 Magnetic tape unit
US8861132B2 (en) 2010-07-06 2014-10-14 International Business Machines Corporation Low friction tape head and system implementing same
US11776565B2 (en) 2022-01-12 2023-10-03 Western Digital Technologies, Inc. Tape head with side-shielded writers and process for making same

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5247413A (en) * 1990-05-16 1993-09-21 Sony Corporation Magnetoresistance effect type thin film magnetic head with noise reducing electrode
JPH06215321A (en) * 1993-01-20 1994-08-05 Hitachi Ltd Dual magnetic head
EP0634739A2 (en) * 1993-07-14 1995-01-18 Sony Corporation Thin-film magnetic head, magnetoresistance effect magnetic head and composite magnetic head
US5764446A (en) * 1996-05-01 1998-06-09 International Business Machines Corporation Magnetic head having an air bearing surface with short-resistant leads
US5978181A (en) * 1997-03-04 1999-11-02 Fujitsu Limited Magnetic head and magnetic recording/reproducing apparatus
US6081409A (en) * 1995-06-07 2000-06-27 International Business Machines Corporation TiC MR-head magnetic shield dummy shield spark gap
US6160688A (en) * 1997-12-16 2000-12-12 Nec Corporation Magneto-resistive composite head and a magnetic disk device, having grounded magnetic shielding layers

Family Cites Families (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1570126A (en) 1977-03-15 1980-06-25 Data Recording Instr Co Manufacture of magnetic heads
US4623867A (en) * 1984-08-13 1986-11-18 Ampex Corporation Permanent magnet biased narrow track magnetoresistive transducer
US4972286A (en) 1989-03-03 1990-11-20 Seagate Technology, Inc. Grounding pole structures in thin film mganetic heads
US5142425A (en) 1990-08-09 1992-08-25 Hewlett-Packard Company Disk drive in which magnetic head-to-disk capacitive coupling is eliminated
EP0477941B1 (en) 1990-09-28 1996-03-06 Sony Corporation Magneto-resistance effect type magnetic head
JP2741837B2 (en) * 1993-08-06 1998-04-22 インターナショナル・ビジネス・マシーンズ・コーポレイション Thin film magnetoresistive head
US5491600A (en) * 1994-05-04 1996-02-13 International Business Machines Corporation Multi-layer conductor leads in a magnetoresistive head
US5663856A (en) 1994-12-06 1997-09-02 Packard; Edward L. Thin film magnetic head with enhanced gap area enhanced by surrounding materials of hard and electrically conductive material
US5539598A (en) * 1994-12-08 1996-07-23 International Business Machines Corporation Electrostatic protection for a shielded MR sensor
US5491605A (en) 1994-12-23 1996-02-13 International Business Machines Corporation Shorted magnetoresistive head elements for electrical overstress and electrostatic discharge protection
JPH1055518A (en) 1996-08-08 1998-02-24 Hitachi Ltd Thin film magnetic head and magnetic disk device
US5757591A (en) * 1996-11-25 1998-05-26 International Business Machines Corporation Magnetoresistive read/inductive write magnetic head assembly fabricated with silicon on hard insulator for improved durability and electrostatic discharge protection and method for manufacturing same
US5850324A (en) * 1997-03-13 1998-12-15 Quantum Corporation Magnetoresistive head having electrically isolated conductor leads
US5829702A (en) * 1997-03-26 1998-11-03 Exabyte Corporation Method and apparatus for counteracting interlayer slip in magnetic tape drive
US6330123B1 (en) * 1999-05-28 2001-12-11 Imation Corp. Head assembly having a single pass servo writer

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5247413A (en) * 1990-05-16 1993-09-21 Sony Corporation Magnetoresistance effect type thin film magnetic head with noise reducing electrode
JPH06215321A (en) * 1993-01-20 1994-08-05 Hitachi Ltd Dual magnetic head
EP0634739A2 (en) * 1993-07-14 1995-01-18 Sony Corporation Thin-film magnetic head, magnetoresistance effect magnetic head and composite magnetic head
US6081409A (en) * 1995-06-07 2000-06-27 International Business Machines Corporation TiC MR-head magnetic shield dummy shield spark gap
US5764446A (en) * 1996-05-01 1998-06-09 International Business Machines Corporation Magnetic head having an air bearing surface with short-resistant leads
US5978181A (en) * 1997-03-04 1999-11-02 Fujitsu Limited Magnetic head and magnetic recording/reproducing apparatus
US6160688A (en) * 1997-12-16 2000-12-12 Nec Corporation Magneto-resistive composite head and a magnetic disk device, having grounded magnetic shielding layers

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 018, no. 587 (P - 1824) 10 November 1994 (1994-11-10) *

Also Published As

Publication number Publication date
KR20040020060A (en) 2004-03-06
DE60224539T2 (en) 2009-01-08
US6760199B2 (en) 2004-07-06
KR100655826B1 (en) 2006-12-11
DE60224539D1 (en) 2008-02-21
JP3999737B2 (en) 2007-10-31
ATE383642T1 (en) 2008-01-15
JP2004537137A (en) 2004-12-09
EP1410384A1 (en) 2004-04-21
EP1410384B1 (en) 2008-01-09
US20030016474A1 (en) 2003-01-23

Similar Documents

Publication Publication Date Title
EP1410384B1 (en) Read/write head assembly
US7548397B2 (en) Magnetic reader with piggybacked fence
US5541793A (en) Bidirectional thin-film magnetoresistive tape head assembly
US6646830B2 (en) Monolithic magnetic read-while-write head apparatus and method of manufacture
US7551393B2 (en) Tape recording head with multiple planes of transducer arrays
US7342748B2 (en) System with matrix array of write heads and matrix array of magnetoresistive (MR) read heads
US7400474B2 (en) Conductive pairing for piggyback magnetic head
US20070047122A1 (en) Tape head having write devices and narrower read devices
US20100227049A1 (en) Magnetic head having selectively defined reader gap thicknesses
US20060152851A1 (en) Planar servo format verifier head
US5764446A (en) Magnetic head having an air bearing surface with short-resistant leads
US7684148B2 (en) Magnetic head with a conductive underlayer above substrate
US20050152066A1 (en) System with matrix array of write heads and array of magnetoresistive (MR) read heads
US8611049B2 (en) Magnetic heads having magnetic films that are more recessed than insulating films, and systems having such heads
US6639753B1 (en) Method of forming a head assembly, a head assembly, and a linear tape drive
US10997994B1 (en) Current-perpendicular-to-plane (CPP) read transducer structure having flux guide and pinned soft bias layer for stabilizing sensor and flux guide
US8238057B2 (en) Magnetic head, head assembly and magnetic recording/reproducing apparatus and method for manufacturing magnetic head
Dee et al. Advanced multi-track tape head for high performance tape recording application
US8015693B2 (en) Method of manufacturing a thin-film magnetic head having a lower magnetic pole projection projecting toward an upper magnetic pole
JPH08153318A (en) Magnetic head and magnetic storage device using the head

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): AE AG AL AM AT AU AZ BA BB BG BY BZ CA CH CN CO CR CU CZ DE DM DZ EC EE ES FI GB GD GE GH HR HU ID IL IN IS JP KE KG KP KR LC LK LR LS LT LU LV MA MD MG MN MW MX MZ NO NZ OM PH PL PT RU SD SE SG SI SK SL TJ TM TN TR TZ UA UG UZ VN YU ZA ZM

Kind code of ref document: A1

Designated state(s): AE AG AL AM AT AU AZ BA BB BG BR BY BZ CA CH CN CO CR CU CZ DE DK DM DZ EC EE ES FI GB GD GE GH GM HR HU ID IL IN IS JP KE KG KP KR KZ LC LK LR LS LT LU LV MA MD MG MK MN MW MX MZ NO NZ OM PH PL PT RO RU SD SE SG SI SK SL TJ TM TN TR TT TZ UA UG UZ VN YU ZA ZM ZW

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): GH GM KE LS MW MZ SD SL SZ UG ZM ZW AM AZ BY KG KZ RU TJ TM AT BE BG CH CY CZ DK EE ES FI FR GB GR IE IT LU MC PT SE SK TR BF BJ CF CG CI GA GN GQ GW ML MR NE SN TD TG

Kind code of ref document: A1

Designated state(s): GH GM KE LS MW MZ SD SL SZ TZ UG ZM ZW AM AZ BY KG KZ MD RU TJ TM AT BE BG CH CY CZ DE DK EE ES FI FR GB GR IE IT LU MC NL PT SE SK TR BF BJ CF CG CI CM GA GN GQ GW ML MR NE SN TD TG

DFPE Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101)
121 Ep: the epo has been informed by wipo that ep was designated in this application
WWE Wipo information: entry into national phase

Ref document number: 2003516052

Country of ref document: JP

WWE Wipo information: entry into national phase

Ref document number: 1020037016794

Country of ref document: KR

WWE Wipo information: entry into national phase

Ref document number: 2002745669

Country of ref document: EP

WWP Wipo information: published in national office

Ref document number: 2002745669

Country of ref document: EP

REG Reference to national code

Ref country code: DE

Ref legal event code: 8642

WWG Wipo information: grant in national office

Ref document number: 2002745669

Country of ref document: EP