Patent Grant
10297275
The present invention relates to data storage systems, and more particularly, this invention relates to magnetic recording modules, in particular, magnetic recording modules having tunnel valve sensors with dissimilar tunnel barrier resistivities.
In magnetic storage systems, magnetic transducers read data from and write data onto magnetic recording media. Data is written on the magnetic recording media by moving a magnetic recording transducer to a position over the media where the data is to be stored. The magnetic recording transducer then generates a magnetic field, which encodes the data into the magnetic media. Data is read from the media by similarly positioning the magnetic read transducer and then sensing the magnetic field of the magnetic media. Read and write operations may be independently synchronized with the movement of the media to ensure that the data can be read from and written to the desired location on the media.
An important and continuing goal in the data storage industry is that of increasing the density of data stored on a medium. For tape storage systems, that goal has led to increasing the track and linear bit density on recording tape, and decreasing the thickness of the magnetic tape medium. However, the development of small footprint, higher performance tape drive systems has created various problems in the design of a tape head assembly for use in such systems.
In a tape drive system, the drive moves the magnetic tape over the surface of the tape head at high speed. Usually the tape head is designed to minimize the spacing between the head and the tape. The spacing between the magnetic head and the magnetic tape is crucial and so goals in these systems are to have the recording gaps of the transducers, which are the source of the magnetic recording flux in near contact with the tape to effect writing sharp transitions, and to have the read elements in near contact with the tape to provide effective coupling of the magnetic field from the tape to the read elements.
An apparatus according to one embodiment includes a module having an array of first read transducers each having a tunnel valve structure and a second read transducer coupled to the array of first read transducers, the second read transducer having a tunnel valve structure. The apparatus also includes a controller, and a cable coupling the read transducers to the controller, thereby forming a plurality of circuits extending from the controller, each circuit corresponding to one of the transducers. Resistances of the circuits are about the same.
An apparatus according to another embodiment includes an array of first read transducers, each first read transducer having a tunnel valve structure configured to read data from a magnetic recording medium. A servo read transducer is coupled to the array of first read transducers, the second read transducer having a tunnel valve structure configured to read servo data from a magnetic recording medium. The resistance of each first read transducer is about the same as the resistance of the servo read transducer.
Any of these embodiments may be implemented in a magnetic data storage system such as a tape drive system, which may include a magnetic head, a drive mechanism for passing a magnetic medium (e.g., recording tape) over the magnetic head, and a controller electrically coupled to the magnetic head.
A process according to one embodiment includes forming a first read transducer having a tunnel valve structure in a first processing sequence, and forming at least a portion of a second read transducer on a common substrate with the first read transducer in a subsequent processing sequence. The servo read transducer has a tunnel valve structure, but the tunnel valve structure of the first read transducer has a different resistivity than the tunnel valve structure of the second read transducer.
Other aspects and embodiments of the present invention will become apparent from the following detailed description, which, when taken in conjunction with the drawings, illustrate by way of example the principles of the invention.
The following description is made for the purpose of illustrating the general principles of the present invention and is not meant to limit the inventive concepts claimed herein. Further, particular features described herein can be used in combination with other described features in each of the various possible combinations and permutations.
Unless otherwise specifically defined herein, all terms are to be given their broadest possible interpretation including meanings implied from the specification as well as meanings understood by those skilled in the art and/or as defined in dictionaries, treatises, etc.
It must also be noted that, as used in the specification and the appended claims, the singular forms “a,” “an” and “the” include plural referents unless otherwise specified.
The following description discloses several preferred embodiments of magnetic storage systems, as well as operation and/or component parts thereof.
In one general embodiment, a tape an apparatus includes a first read transducer having a tunnel valve structure, and a second read transducer coupled to the first read transducer. The second read transducer has a tunnel valve structure as well, but the tunnel valve structure of the first read transducer has a different resistivity than the tunnel valve structure of the second read transducer.
In another general embodiment, an apparatus includes an array of first read transducers, each first read transducer having a tunnel valve structure. At least a second read transducer is coupled to the first read transducers, the second read transducer having a tunnel valve structure. The tunnel valve structure of the first read transducer has a different resistivity than the tunnel valve structure of the second read transducer.
Any of these embodiments may be implemented in a magnetic data storage system such as a tape drive system, which may include a magnetic head, a drive mechanism for passing a magnetic medium (e.g., recording tape) over the magnetic head, and a controller electrically coupled to the magnetic head.
In another general embodiment, a process includes forming a first read transducer having a tunnel valve structure in a first processing sequence, and forming at least a portion of a second read transducer on a common substrate with the first read transducer in a subsequent processing sequence. The second read transducer has a tunnel valve structure, but the tunnel valve structure of the first read transducer has a different resistivity than the tunnel valve structure of the second read transducer.
As shown, a tape supply cartridge 120 and a take-up reel 121 are provided to support a tape 122. One or more of the reels may form part of a removable cartridge and are not necessarily part of the system 100. The tape drive, such as that illustrated in
Guides 125 guide the tape 122 across the tape head 126. Such tape head 126 is in turn coupled to a controller 128 via a cable 130. The controller 128 may be or include a processor and/or any logic for controlling any subsystem of the drive 100. For example, the controller 128 typically controls head functions such as servo following, data writing, data reading, etc. The controller 128 may include at least one servo channel and at least one data channel, each of which include data flow processing logic configured to process and/or store information to be written to and/or read from the tape 122. The controller 128 may operate under logic known in the art, as well as any logic disclosed herein, and thus may be considered as a processor for any of the descriptions of tape drives included herein, in various embodiments. The controller 128 may be coupled to a memory 136 of any known type, which may store instructions executable by the controller 128. Moreover, the controller 128 may be configured and/or programmable to perform or control some or all of the methodology presented herein. Thus, the controller 128 may be considered to be configured to perform various operations by way of logic programmed into one or more chips, modules, and/or blocks; software, firmware, and/or other instructions being available to one or more processors; etc., and combinations thereof.
The cable 130 may include a plurality of read/write circuits extending between the controller and the transducers to transmit data to the head 126 to be recorded on the tape 122 and to receive data read by the head 126 from the tape 122. An actuator 132 controls position of the head 126 relative to the tape 122.
An interface 134 may also be provided for communication between the tape drive 100 and a host (internal or external) to send and receive the data and for controlling the operation of the tape drive 100 and communicating the status of the tape drive 100 to the host, all as will be understood by those of skill in the art.
By way of example,
The substrates 204A are typically constructed of a wear resistant material, such as a ceramic. The closures 204B may be made of the same or similar ceramic as the substrates 204A.
The readers and writers may be arranged in a piggyback or merged configuration. An illustrative piggybacked configuration comprises a (magnetically inductive) writer transducer on top of (or below) a (magnetically shielded) reader transducer (e.g., a magnetoresistive reader, etc.), wherein the poles of the writer and the shields of the reader are generally separated. An illustrative merged configuration comprises one reader shield in the same physical layer as one writer pole (hence, “merged”). The readers and writers may also be arranged in an interleaved configuration. Alternatively, each array of channels may be readers or writers only. Any of these arrays may contain one or more servo track readers for reading servo data on the medium.
In this example, the tape 208 includes 4 to 32 data bands, e.g., with 16 data bands and 17 servo tracks 210, as shown in
Several R/W pairs 222 may be present, such as 8, 16, 32 pairs, etc. The R/W pairs 222 as shown are linearly aligned in a direction generally perpendicular to a direction of tape travel thereacross. However, the pairs may also be aligned diagonally, etc. Servo readers 212 are positioned on the outside of the array of R/W pairs, the function of which is well known.
Generally, the magnetic tape medium moves in either a forward or reverse direction as indicated by arrow 220. The magnetic tape medium and head assembly 200 operate in a transducing relationship in the manner well-known in the art. The piggybacked MR head assembly 200 includes two thin-film modules 224 and 226 of generally identical construction.
Modules 224 and 226 are joined together with a space present between closures 204B thereof (partially shown) to form a single physical unit to provide read-while-write capability by activating the writer of the leading module and reader of the trailing module aligned with the writer of the leading module parallel to the direction of tape travel relative thereto. When a module 224, 226 of a piggyback head 200 is constructed, layers are formed in the gap 218 created above an electrically conductive substrate 204A (partially shown), e.g., of AlTiC, in generally the following order for the R/W pairs 222: an insulating layer 236, a first shield 232 typically of an iron alloy such as NiFe (—), cobalt zirconium tantalum (CZT) or Al—Fe—Si (Sendust), a sensor 234 for sensing a data track on a magnetic medium, a second shield 238 typically of a nickel-iron alloy (e.g., ˜80/20 at % NiFe, also known as permalloy), first and second writer pole tips 228, 230, and a coil (not shown). The sensor may be of any known type, including those based on MR, GMR, AMR, tunneling magnetoresistance (referred to as tunnel valve and TMR), etc.
The first and second writer poles 228, 230 may be fabricated from high magnetic moment materials such as ˜45/55 NiFe. Note that these materials are provided by way of example only, and other materials may be used. Additional layers such as insulation between the shields and/or pole tips and an insulation layer surrounding the sensor may be present. Illustrative materials for the insulation include alumina and other oxides, insulative polymers, etc.
The configuration of the tape head 126 according to one embodiment includes multiple modules, preferably three or more. In a write-read-write (W-R-W) head, outer modules for writing flank one or more inner modules for reading. Referring to
In one embodiment, the tape bearing surfaces 308, 310, 312 of the first, second and third modules 302, 304, 306 lie on about parallel planes (which is meant to include parallel and nearly parallel planes, e.g., between parallel and tangential as in
Where the tape bearing surfaces 308, 310, 312 lie along parallel or nearly parallel yet offset planes, intuitively, the tape should peel off of the tape bearing surface 308 of the leading module 302. However, the vacuum created by the skiving edge 318 of the leading module 302 has been found by experimentation to be sufficient to keep the tape adhered to the tape bearing surface 308 of the leading module 302. The trailing edge 320 of the leading module 302 (the end from which the tape leaves the leading module 302) is the approximate reference point which defines the wrap angle α2 over the tape bearing surface 310 of the second module 304. The tape stays in close proximity to the tape bearing surface until close to the trailing edge 320 of the leading module 302. Accordingly, read and/or write elements 322 may be located near the trailing edges of the outer modules 302, 306. These embodiments are particularly adapted for write-read-write applications.
A benefit of this and other embodiments described herein is that, because the outer modules 302, 306 are fixed at a determined offset from the second module 304, the inner wrap angle α2 is fixed when the modules 302, 304, 306 are coupled together or are otherwise fixed into a head. The inner wrap angle α2 is approximately tan−1(δ/W) where δ is the height difference between the planes of the tape bearing surfaces 308, 310 and W is the width between the opposing ends of the tape bearing surfaces 308, 310. An illustrative inner wrap angle α2 is in a range of about 0.3° to about 1.1°, though can be any angle required by the design.
Beneficially, the inner wrap angle α2 on the side of the module 304 receiving the tape (leading edge) will be larger than the inner wrap angle α3 on the trailing edge, as the tape 315 rides above the trailing module 306. This difference is generally beneficial as a smaller α3 tends to oppose what has heretofore been a steeper exiting effective wrap angle.
Note that the tape bearing surfaces 308, 312 of the outer modules 302, 306 are positioned to achieve a negative wrap angle at the trailing edge 320 of the leading module 302. This is generally beneficial in helping to reduce friction due to contact with the trailing edge 320, provided that proper consideration is given to the location of the crowbar region that forms in the tape where it peels off the head. This negative wrap angle also reduces flutter and scrubbing damage to the elements on the leading module 302. Further, at the trailing module 306, the tape 315 flies over the tape bearing surface 312 so there is virtually no wear on the elements when tape is moving in this direction. Particularly, the tape 315 entrains air and so will not significantly ride on the tape bearing surface 312 of the third module 306 (some contact may occur). This is permissible, because the leading module 302 is writing while the trailing module 306 is idle.
Writing and reading functions are performed by different modules at any given time. In one embodiment, the second module 304 includes a plurality of data and optional servo readers 331 and no writers. The first and third modules 302, 306 include a plurality of writers 322 and no data readers, with the exception that the outer modules 302, 306 may include optional servo readers. The servo readers may be used to position the head during reading and/or writing operations. The servo reader(s) on each module are typically located towards the end of the array of readers or writers.
By having only readers or side by side writers and servo readers in the gap between the substrate and closure, the gap length can be substantially reduced. Typical heads have piggybacked readers and writers, where the writer is formed above each reader. A typical gap is 20-35 microns. However, irregularities on the tape may tend to droop into the gap and create gap erosion. Thus, the smaller the gap is the better. The smaller gap enabled herein exhibits fewer wear related problems.
In some embodiments, the second module 304 has a closure, while the first and third modules 302, 306 do not have a closure. Where there is no closure, preferably a hard coating is added to the module. One preferred coating is diamond-like carbon (DLC).
In the embodiment shown in
With reduced-thickness ceramic or thin film closures 334, 336 or no closures on the outer modules 302, 306, the write-to-read gap spacing can be reduced to less than about 1 mm, e.g., about 0.75 mm, or 50% less than commonly-used LTO tape head spacing. The open space between the modules 302, 304, 306 can still be set to approximately 0.5 to 0.6 mm, which in some embodiments is ideal for stabilizing tape motion over the second module 304.
Depending on tape tension and stiffness, it may be desirable to angle the tape bearing surfaces of the outer modules relative to the tape bearing surface of the second module.
Typically, the tape wrap angles may be set about midway between the embodiments shown in
Additional aspects of the embodiments shown in
A 32 channel version of a multi-module head 126 may use cables 350 having leads on the same or smaller pitch as current 16 channel piggyback LTO modules, or alternatively the connections on the module may be organ-keyboarded for a 50% reduction in cable span. Over-under, writing pair unshielded cables may be used for the writers, which may have integrated servo readers.
The outer wrap angles α1 may be set in the drive, such as by guides of any type known in the art, such as adjustable rollers, slides, etc. or alternatively by outriggers, which are integral to the head. For example, rollers having an offset axis may be used to set the wrap angles. The offset axis creates an orbital arc of rotation, allowing precise alignment of the wrap angle α1.
To assemble any of the embodiments described above, conventional u-beam assembly can be used. Accordingly, the mass of the resultant head may be maintained or even reduced relative to heads of previous generations. In other approaches, the modules may be constructed as a unitary body. Those skilled in the art, armed with the present teachings, will appreciate that other known methods of manufacturing such heads may be adapted for use in constructing such heads. Moreover, unless otherwise specified, processes and materials of types known in the art may be adapted for use in various embodiments in conformance with the teachings herein, as would become apparent to one skilled in the art upon reading the present disclosure.
As a tape is run over a module, it is preferred that the tape passes sufficiently close to magnetic transducers on the module such that reading and/or writing is efficiently performed, e.g., with a low error rate. According to some approaches, tape tenting may be used to ensure the tape passes sufficiently close to the portion of the module having the magnetic transducers. To better understand this process,
It follows that tape tenting may be used to direct the path of a tape as it passes over a module. As previously mentioned, tape tenting may be used to ensure the tape passes sufficiently close to the portion of the module having the magnetic transducers, preferably such that reading and/or writing is efficiently performed, e.g., with a low error rate.
Magnetic tapes may be stored in tape cartridges that are, in turn, stored at storage slots or the like inside a data storage library. The tape cartridges may be stored in the library such that they are accessible for physical retrieval. In addition to magnetic tapes and tape cartridges, data storage libraries may include data storage drives that store data to, and/or retrieve data from, the magnetic tapes. Moreover, tape libraries and the components included therein may implement a file system which enables access to tape and data stored on the tape.
File systems may be used to control how data is stored in, and retrieved from, memory. Thus, a file system may include the processes and data structures that an operating system uses to keep track of files in memory, e.g., the way the files are organized in memory. Linear Tape File System (LTFS) is an exemplary format of a file system that may be implemented in a given library in order to enables access to compliant tapes. It should be appreciated that various embodiments herein can be implemented with a wide range of file system formats, including for example IBM Spectrum Archive Library Edition (LTFS LE). However, to provide a context, and solely to assist the reader, some of the embodiments below may be described with reference to LTFS which is a type of file system format. This has been done by way of example only, and should not be deemed limiting on the invention defined in the claims.
A tape cartridge may be “loaded” by inserting the cartridge into the tape drive, and the tape cartridge may be “unloaded” by removing the tape cartridge from the tape drive. Once loaded in a tape drive, the tape in the cartridge may be “threaded” through the drive by physically pulling the tape (the magnetic recording portion) from the tape cartridge, and passing it above a magnetic head of a tape drive. Furthermore, the tape may be attached on a take-up reel (e.g., see 121 of
Once threaded in the tape drive, the tape in the cartridge may be “mounted” by reading metadata on a tape and bringing the tape into a state where the LTFS is able to use the tape as a constituent component of a file system. Moreover, in order to “unmount” a tape, metadata is preferably first written on the tape (e.g., as an index), after which the tape may be removed from the state where the LTFS is allowed to use the tape as a constituent component of a file system. Finally, to “unthread” the tape, the tape is unattached from the take-up reel and is physically placed back into the inside of a tape cartridge again. The cartridge may remain loaded in the tape drive even after the tape has been unthreaded, e.g., waiting for another read and/or write request. However, in other instances, the tape cartridge may be unloaded from the tape drive upon the tape being unthreaded, e.g., as described above.
Magnetic tape is a sequential access medium. Thus, new data is written to the tape by appending the data at the end of previously written data. It follows that when data is recorded in a tape having only one partition, metadata (e.g., allocation information) is continuously appended to an end of the previously written data as it frequently updates and is accordingly rewritten to tape. As a result, the rearmost information is read when a tape is first mounted in order to access the most recent copy of the metadata corresponding to the tape. However, this introduces a considerable amount of delay in the process of mounting a given tape.
To overcome this delay caused by single partition tape mediums, the LTFS format includes a tape that is divided into two partitions, which include an index partition and a data partition. The index partition may be configured to record metadata (meta information), e.g., such as file allocation information (Index), while the data partition may be configured to record the body of the data, e.g., the data itself.
Looking to
As index information is updated, it preferably overwrites the previous version of the index information, thereby allowing the currently updated index information to be accessible at the beginning of tape in the index partition. According to the specific example illustrated in
The metadata may be updated in the index partition 902 and/or the data partition 904 differently depending on the desired embodiment. According to some embodiments, the metadata of the index partition 902 may be updated in response to the tape being unmounted, e.g., such that the index may be read from the index partition when that tape is mounted again. The metadata may also be written in the data partition 902 so the tape may be mounted using the metadata recorded in the data partition 902, e.g., as a backup option.
According to one example, which is no way intended to limit the invention, LTFS LE may be used to provide the functionality of writing an index in the data partition when a user explicitly instructs the system to do so, or at a time designated by a predetermined period which may be set by the user, e.g., such that data loss in the event of sudden power stoppage can be mitigated.
As data density increases, track widths are reduced to accommodate more tracks per tape for more data. Thus, the data readers become smaller to fit the decreasing widths of the tracks. However, in conventional tape recording heads, servo track readers (see
Conventional methods to build the tunnel valve sensors involve blanket depositions to create these tunnel valve structures and the depositions are common (i.e., the same) for both data and servo elements. Thus, the data and servo elements are built concurrently with the same materials and processes. With increasing numbers of tracks, because the track widths are reduced, the data reader dimensions must be reduced. For efficient data reading, the reader widths are adjusted according to track width. When data reader dimensions are reduced to enable reading smaller track widths that are required for high density recording, tunnel barrier resistivity is also reduced to preserve data reader resistances.
Tunnel barrier resistivity may be calculated according to Equation 1.
R=RA/(w×h) Equation 1
For example, if a data sensor has an RA of 4Ω μm2 and sensor dimensions of w=0.2 μm, h=0.2 μm, then the data sensor resistance (R)=100Ω. On the other hand, servo readers may have w=2 μm and h=0.6 μm with R=3Ω But R may preferably be 30-80Ω in some embodiments. Thus, RA for servo readers would need to be about 40-60Ω μm2.
Servo reader dimensions have historically remained constant. Conventional servo readers are constrained to have widths in the 2 μm range to accommodate position error signaling issues and backward compatibility with earlier generation of products. Thus, in conventional heads, a RA of 4Ω μm2, but with servo reader dimensions of w=2.0 μm, h=0.6 μm, the servo resistance (R) would be 3.3Ω, and thus, too low for signal processing of the servo signal.
There are no known solutions to this problem for servo readers in a multichannel reading module having tunnel valve transducers.
Various embodiments described herein include using material with different RA values for the servo sensors thereby allowing servo reader resistance to remain about the same from generation to generation while the tunnel barrier resistivity of the data readers may be reduced, thereby enabling narrower reader width heads having acceptable resistance values. Methods described herein involve forming the servo reader tunnel barrier layers independent of the data reader tunnel barrier layers.
One embodiment of an apparatus includes a first read transducer having a tunnel valve structure and a second read transducer coupled to the first read transducer where the second read transducer has a tunnel valve structure. Furthermore, the tunnel valve structure of the first read transducer has a different resistivity than the tunnel valve structure of the second read transducer.
According to one embodiment of apparatus 1000, the tunnel valve structure 1006 may include basically anything between the spacer layers 1011 which provide a non-magnetic electrical connection to the shields, and excluding layers along the side edges of the trimmed sensor stack (e.g., excluding hard bias layers 1002 and insulating layers 1026, as shown in
According to one embodiment of apparatus 1000, a second read transducer 1010 may be coupled to the first read transducer 1012, the second read transducer 1010 having a tunnel valve structure 1004, where the tunnel valve structure 1006 of the first read transducer 1012 has a different resistivity than the tunnel valve structure 1004 of the second read transducer 1010. The difference in resistivity is intentional, and more than found in mere process variations.
In order to maintain a constant resistance, the tunnel barrier resistivity may be scaled in consideration of the area, according to Equation 1 (see above). For example, the difference in RA values for the tunnel valve structure 1004 of the first read transducer 1010 compared to the tunnel valve structure 1006 of the second read transducer 1012 would be more than about 20%.
Looking to a magnified view (Circle 10C) of the tunnel valve structure 1004 of the second read transducer 1010, as shown in
In various embodiments of apparatus 1000, and as shown in the magnified views of
According to one embodiment, the first read transducer 1012 may be a data reader and the second read transducer 1010 may be a servo reader. In such a case, for example, but not limited to this example, a servo reader sensor 1010 may include a tunnel barrier material with an RA of 20Ω μm2 that is five times greater than the RA of the tunnel barrier material of the data reader 1012, which in this example is thus 4Ω μm2. Thus, as calculated from Equation 1 and shown in Equation 2 below, a servo reading sensor having 2.0 μm width and 0.2 μm height, the servo resistance would be 25Ω, a suitable resistance for position error signaling in some embodiments.
R=25Ω=20/(2.0×0.4) Equation 2
In some approaches, assuming use of a magnesium oxide (MgO) tunnel valve system, a factor of five increase in RA may only represent an increase of approximately 0.3 nm in MgO thickness (for example, in the direction of deposition (d) thickness in
In some approaches, the resistivity of the tunnel valve structure 1006 of the first read transducer 1012 may be higher than the resistivity of the tunnel valve structure 1004 of the second read transducer 1010. In other approaches, the resistivity of the tunnel valve structure 1006 of the first read transducer 1012 may be lower than the resistivity of the tunnel valve structure 1004 of the second read transducer 1010.
In one embodiment of apparatus 1000, the first read transducer 1012 may be one read transducer 1012 in an array 1001 of first read transducers. Moreover, the second read transducer 1010 may be aligned with a longitudinal axis 1003 direction of the array 1001.
One embodiment of apparatus 1000 includes an array 1001 of first read transducers 1012, of which each first read transducer 1012 may have a tunnel valve structure 1006. In some approaches, the apparatus 1000 may have at least a second read transducer 1010 coupled to the first read transducers 1012. In addition, the second read transducer 1010 may have a tunnel valve structure 1004, where the tunnel valve structure 1006 of the first read transducer 1012 may have a different resistivity than the tunnel valve structure 1004 of the second read transducer 1010.
In one embodiment of apparatus 1000, the read transducers 1010, 1012, in an array 1001, etc. may be in a magnetic tape head. Furthermore, in some approaches, apparatus 1000 includes a drive mechanism for passing a magnetic medium over the read transducers (e.g., as illustrated in
Track widths for data readers may change from generation to generation of tape recording products. Thus, various embodiments described below allow different data reader widths to accommodate changing track widths and various formats. Magnetic tape heads may be formed with data readers aligned according to a specification format to read multiple generations of tapes with different track widths. In addition, new generations may require more channels.
In one embodiment of apparatus 1100 as shown in
In various embodiments, the width of the tunnel barrier layer of the tunnel valve structure may vary within an array of data readers. For example, according to one embodiment of apparatus 1102,
An example of another embodiment of a multiformat apparatus may have multiple arrays of different resistivities of the data readers and/or servo readers, for example, in a multi-format head having multiple arrays. As illustrated in
In various embodiments, e.g., any of the foregoing embodiments, the second read transducer and another second read transducer may be aligned with a longitudinal axis of the array.
Unless otherwise disclosed herein, conventional techniques may be used and modified to conform to the following discussion.
According to one embodiment of the process 1200, step 1202 involves forming a first read transducer having a tunnel valve structure in a first processing sequence.
An exemplary embodiment 1300 of the process 1200 is illustrated in
Step 1304 involves applying a photoresist 1316 by conventional methods on top of the first reader transducer material 1314. The photoresist 1316 material is applied and developed to form a mask that allows regions 1303 to be removed. This is followed by etching the regions 1303 of first reader transducer material 1314 exposed upon removing the photoresist regions 1303 in step 1306.
In one approach, step 1306 in
In one approach, most or all the first reader transducer material 1314 is removed from the region 1303. Thus, the first reader transducer RA material is removed from regions that will have servo reader transducer having different RA. In another approach, the etching may proceed until the tunnel barrier material is removed, e.g., using a combination of milling and wet etching.
Referring back to
According to the exemplary embodiment 1300 in
Step 1310 of the exemplary embodiment 1300 involves removing the photoresist 1316 mask material and overlying material, e.g., using a conventional lift off process. The second reader transducer material 1318 remains in the regions 1303.
Step 1312 of the exemplary embodiment 1300 involves defining the heights and/or track widths for the sensors simultaneously using photoresist material 1320 following conventional techniques to. In some approaches, the height for the sensors formed from the first read transducer material 1314 may be smaller than the height for the sensors formed from the second read transducer material 1318.
Following step 1312 of exemplary embodiment 1300 and step 1204 of the process 1200, conventional tape head processing may proceed following conventional methods known in the art. In exemplary processes, the tunnel valve servo thickness may only change by 0.1 nm of the total thickness of tunnel valve material, which is typically about 35 nm or about 1 part in 350.
Referring to the resulting structure of step 1312 in
In various embodiments of the resulting structure of step 1312, the resistance of the tunnel valve structure 1326 of the first data reader may be about the same as the resistance of the tunnel valve structure 1324 of the second data reader along a plane of deposition thereof. However, the resistances of the various tunnel valve structures 1326, etc. may be different. Similarly, where a plurality 1328 of first data readers may be present, the resistance range may be similar or different than the resistance or resistance range of the tunnel valve structure(s) 1324 of the second data reader(s).
In some approaches of process 1200, the first read transducer may be a data reader, wherein the second read transducer may be a servo reader.
It will be clear that the various features of the foregoing systems and/or methodologies may be combined in any way, creating a plurality of combinations from the descriptions presented above.
It will be further appreciated that embodiments of the present invention may be provided in the form of a service deployed on behalf of a customer.
The inventive concepts disclosed herein have been presented by way of example to illustrate the myriad features thereof in a plurality of illustrative scenarios, embodiments, and/or implementations. It should be appreciated that the concepts generally disclosed are to be considered as modular, and may be implemented in any combination, permutation, or synthesis thereof. In addition, any modification, alteration, or equivalent of the presently disclosed features, functions, and concepts that would be appreciated by a person having ordinary skill in the art upon reading the instant descriptions should also be considered within the scope of this disclosure.
While various embodiments have been described above, it should be understood that they have been presented by way of example only, and not limitation. Thus, the breadth and scope of an embodiment of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.
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| Number | Date | Country | |
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| 20180166098 A1 | Jun 2018 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 15377790 | Dec 2016 | US |
| Child | 15469322 | US |
