CN113808625B - Two-dimensional magnetic recording reader with dual free layer magnetic tunnel junction - Google Patents
Two-dimensional magnetic recording reader with dual free layer magnetic tunnel junction Download PDFInfo
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Abstract
The application provides a two-dimensional magnetic recording reader with a dual free layer magnetic tunnel junction. The present disclosure relates generally to a two-dimensional magnetic recording (TDMR) read head with a Magnetic Tunnel Junction (MTJ). Both the upper reader and the lower reader have a Dual Free Layer (DFL) MTJ structure between two shields. A Synthetic Antiferromagnetic (SAF) soft bias structure defines the MTJ and a post hard bias (RHB) structure is disposed behind the MTJ. The DFL MTJ reduces the distance between the upper and lower readers and thus improves Areal Density Capability (ADC). Further, the SAF soft bias structure and the back bias structure cause the dual free layer MTJ to have a scissors state magnetic moment at a Media Facing Surface (MFS).
Description
Technical Field
Embodiments of the present disclosure generally relate to a Dual Free Layer (DFL) Magnetic Tunnel Junction (MTJ) two-dimensional magnetic recording (TDMR) read head.
Background
A two-dimensional magnetic recording (TDMR) read head has a first sensor, often referred to as a lower reader, and a second sensor, often referred to as an upper reader. The readers each have a lower and an upper shield with an insulating Reader Separation Gap (RSG) therebetween.
TDMR read heads typically have an MTJ structure with an antiferromagnetic layer, a synthetic antiferromagnetic pinning layer (SAF PL), an insulation barrier thereon, and a free magnetic layer. A capping layer may optionally be present on the free magnetic layer. The free magnetic layer is longitudinally biased with respect to the sides of the MTJ structure by a soft bias layer. Both the top reader and the bottom reader are substantially identical.
The TDMR structure of the SAF PL is not very reliable because separate anneals for the upper and lower readers are required in order to effectively pin the SAF PL. In order for the SAF PL to have a desired crystallinity, the SAF PL is annealed within a limited annealing range. If there is no desired crystallinity, the lower reader MTJ may suffer from performance degradation due to atomic interdiffusion at high temperatures. In addition, the SAF PL is very thick, which increases the distance between the upper reader and the lower reader in the downstream track direction, thereby reducing the Areal Density Capability (ADC).
Accordingly, there is a need in the art for an improved TDMR and method of manufacture.
Disclosure of Invention
The present disclosure relates generally to a two-dimensional magnetic recording (TDMR) read head with a Magnetic Tunnel Junction (MTJ). Both the upper reader and the lower reader have a Dual Free Layer (DFL) MTJ structure between two shields. A Synthetic Antiferromagnetic (SAF) Soft Bias (SB) structure defines the MTJ and a post hard bias (RHB) structure is disposed behind the MTJ. The DFL MTJ reduces the distance between the upper and lower readers and thus improves the Areal Density Capability (ADC). Furthermore, the SAF SB structure and the RHB structure cause the DFL MTJ to have a scissors state magnetic moment at the Medium Facing Surface (MFS).
In one embodiment, a two-dimensional magnetic recording (TDMR) head includes: a first reader, comprising: a first lower shield; a first Dual Free Layer (DFL) sensor disposed over the first lower shield; and a first upper shield disposed over the first DFL sensor; an insulating reader separation gap disposed above the first reader; and a second reader disposed over the insulated reader separation gap, the second reader comprising: a second lower shield; a second DFL sensor disposed over the second lower shield; and a second upper shield disposed over the second DFL sensor.
In another embodiment, a two-dimensional magnetic recording (TDMR) head includes: a first reader, comprising: a first lower shield; a first sensor disposed over the first lower shield; a first upper shield disposed over the first sensor; and a first rear hard bias structure disposed behind the first sensor; an insulating reader separation gap disposed above the first reader; and a second reader disposed over the insulated reader separation gap, the second reader comprising: a second lower shield; a second sensor disposed over the second lower shield; a second upper shield disposed over the second sensor; and a second rear hard bias structure disposed behind the second sensor.
In another embodiment, a two-dimensional magnetic recording (TDMR) head includes: a first reader, comprising: a first lower shield; a first sensor disposed over the first lower shield; a first upper shield disposed over the first sensor; and a first Synthetic Antiferromagnetic (SAF) Soft Bias (SB) structure disposed adjacent to the first sensor; an insulating reader separation gap disposed above the first reader; and a second reader disposed over the insulated reader separation gap, the second reader comprising: a second lower shield; a second sensor disposed over the second lower shield; a second upper shield disposed over the second sensor; and a second SAF SB structure disposed adjacent to the second sensor.
Drawings
So that the manner in which the above recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this disclosure and are therefore not to be considered limiting of its scope, for the disclosure may admit to other equally effective embodiments.
FIG. 1 is a schematic illustration of certain embodiments of a magnetic media drive incorporating a magnetic read head.
FIG. 2 is a schematic illustration of certain embodiments of a cross-sectional side view of a head assembly facing a magnetic storage medium.
Fig. 3A-3D are schematic illustrations of a Dual Free Layer (DFL) readhead according to various embodiments.
FIGS. 4A-4C are schematic illustrations of a TDMR read head according to one embodiment.
FIG. 5 is a flowchart illustrating a method of fabricating a TDMR read head according to one embodiment.
6A-6H are schematic illustrations of a TDMR read head at various stages of manufacture.
To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements disclosed in one embodiment may be beneficially utilized on other embodiments without specific recitation.
Detailed Description
Hereinafter, reference is made to embodiments of the present disclosure. However, it should be understood that the disclosure is not limited to specific described embodiments. Indeed, any combination of the following features and elements, whether related to different embodiments or not, is contemplated to implement and practice the present disclosure. Moreover, although embodiments of the present disclosure may achieve advantages over other possible solutions and/or over the prior art, whether a particular advantage is achieved by a given embodiment is not limiting of the present disclosure. The following aspects, features, embodiments and advantages are therefore merely illustrative and are not considered elements or limitations of the appended claims except where explicitly recited in a claim. Likewise, references to "the present disclosure" should not be construed as a generalization of any inventive subject matter disclosed herein and should not be considered to be an element or limitation of the appended claims except where explicitly recited in a claim.
The present disclosure relates generally to a two-dimensional magnetic recording (TDMR) read head with a Magnetic Tunnel Junction (MTJ). Both the upper reader and the lower reader have a Dual Free Layer (DFL) MTJ structure between two shields. A Synthetic Antiferromagnetic (SAF) Soft Bias (SB) structure defines the MTJ and a post hard bias (RHB) structure is disposed behind the MTJ. The DFL MTJ reduces the distance between the upper and lower readers and thus improves the Areal Density Capability (ADC). Furthermore, the SAF SB structure and the RHB structure cause the DFL MTJ to have a scissors state magnetic moment at the Medium Facing Surface (MFS).
FIG. 1 is a schematic illustration of certain embodiments of a magnetic media drive 100 that includes a magnetic write head and a magnetic read head. The magnetic medium drive 100 may be a single drive/device or may include multiple drives/devices. Magnetic media drive 100 comprises a magnetic recording medium, such as one or more rotatable disks 112 supported on a spindle 114 and rotated by a drive motor 118. For ease of illustration, a single disk drive according to one embodiment is shown. The magnetic recording on each disk 112 is in the form of any suitable pattern of data tracks, such as a circular pattern of concentric data tracks (not shown) on the disk 112.
At least one slider 113 is positioned near the magnetic disk 112. Each slider 113 supports a head assembly 121 that includes one or more read/write heads, such as a write head and a read head comprising a TMR device. As the magnetic disk 112 rotates, the slider 113 moves radially in and out across the disk surface 122 so that the head assembly 121 can access different tracks of the magnetic disk 112 where data needs to be written or read. Each slider 113 is attached to an actuator arm 119 by means of a suspension 115. Suspension 115 provides a slight spring force that biases slider 113 toward disk surface 122. Each actuator arm 119 is attached to an actuator 127. The actuator 127 as shown in fig. 1 may be a Voice Coil Motor (VCM). The VCM comprises a coil movable within a fixed magnetic field, the direction and speed of the coil movements being controlled by the motor current signals supplied by control unit 129.
During operation of the magnetic media drive 100, rotation of the magnetic disk 112 generates an air or gas bearing between the slider 113 and the disk surface 122, which exerts an upward force or lift on the slider 113. The air or gas bearing thus counter balances the slight spring force of suspension 115 and supports slider 113 off and slightly above disk surface 122 by a small, substantially constant spacing during normal operation.
The various components of the magnetic media drive 100 are controlled in operation by control signals generated by the control unit 129, such as access control signals and internal clock signals. Typically, the control unit 129 comprises logic control circuits, storage means and a microprocessor. The control unit 129 generates control signals to control various system operations such as drive motor control signals on line 123 and head position and seek control signals on line 128. The control signals on line 128 provide the desired current profile to optimally move and position slider 113 to the desired data track on disk 112. Write signals and read signals are communicated to and from head assembly 121 by way of recording channel 125. Some embodiments of the magnetic media drive of FIG. 1 may further comprise multiple media or disks, multiple actuators, and/or multiple sliders.
FIG. 2 is a schematic illustration of certain embodiments of a cross-sectional side view of a head assembly 200 facing a magnetic disk 112 or other magnetic storage medium. Head assembly 200 may correspond to head assembly 121 described in fig. 1. The head assembly 200 includes a Media Facing Surface (MFS) 212 that faces the disk 112. As shown in fig. 2, the magnetic disk 112 moves relatively in the direction indicated by arrow 232 and the head assembly 200 moves relatively in the direction indicated by arrow 233.
The head assembly 200 includes a magnetic read head 211. The magnetic read head 211 includes a first sensing element 204a disposed between shields S1 and S2, and a second sensing element 204b disposed between shields S2 and S3. The sensing elements 204a, 204b and shields S1, S2, and S3 each have surfaces facing the disk 112 at the MFS 212. In one embodiment, the sensing elements 204a, 204b are TMR devices that sense the magnetic field of a recording bit, such as a perpendicular recording bit or a longitudinal recording bit, in the magnetic disk 112 by a TMR effect. In certain embodiments, the spacing between shields S1 and S2 and the spacing between shields S2 and S3 is about 17nm or less.
The head assembly 200 may include a write head 210. The write head 210 includes a main pole 220, a leading shield 206, and a Trailing Shield (TS) 240. The main pole 220 includes a magnetic material and serves as a main electrode. Each of the main pole 220, the leading shield 206, and the TS 240 has a front portion at the MFS 212. The write head 210 includes a coil 218 surrounding a main pole 220 that excites the main pole 220 to produce a write magnetic field used to affect the magnetic recording medium of the rotatable disk 112. The coil 218 may be a helical structure or one or more sets of flat structures. TS 240 includes magnetic material that acts as a return pole for main pole 220. The leading shield 206 may provide electromagnetic shielding and be separated from the main pole 220 by a leading gap 254.
Fig. 3A-3D are schematic illustrations of a DFL readhead 300. FIG. 3A is an ABS view of the read head 300. The read head 300 includes a first shield (S1) 302, a seed layer 304, a first Free Layer (FL) 306, a barrier layer 308, a second FL310, a cap layer 312, and a second shield (S2) 322. The seed layer 304 comprises a material selected from the group consisting of tantalum (Ta), tungsten (W), and combinations thereof. In one embodiment, barrier layer 308 comprises MgO. The read head 300 further includes a first Synthetic Antiferromagnetic (SAF) Soft Bias (SB) (e.g., a side shield) that includes a first lower SB 316a, a first spacer 318a (e.g., ruthenium), and a first upper SB 320a; and a second SAF SB comprising a second lower SB 316b, a second spacer 318b (e.g., ruthenium), and a second upper SB 320b. The magnetic moments for the first FL 306 and the second FL310 may be antiparallel due to an antiparallel bias from the SAF SB.
Fig. 3B is an APEX view of the readhead 300. The read head 300 further includes a Rear Hard Bias (RHB) 346 and an insulator 352. Insulator 352 may be aluminum oxide (AlOx) or any other suitable insulating material. The RHB 346 generates a magnetic field directed away from the insulator 352 and toward the following layers: a first FL 306, a barrier layer 308, a second FL310, and a cap layer 312.RHB 346 can include cobalt platinum (CoPt) and it is magnetically decoupled from shield 322 by interposing nonmagnetic layer 360 between 346 and 322.
FIG. 3C is a schematic illustration of a Magnetic Tunnel Junction (MTJ) stack 350 of the read head 300 according to an embodiment. The MTJ stack 350 includes a seed layer 304, a first FL 306, a barrier layer 308, a second FL310, and a cap layer 312.
FIG. 3D is a top view of the read head 300 showing the response of the MTJ stack 350 to an external magnetic field. The RHB 346 generates a magnetic field directed toward the MTJ stack 350. The RHB 346 is formed behind the MTJ stack 350. The magnetic moments of the first FL 306 and the second FL310 are tilted toward each SB. The resulting magnetic moment may be referred to as a "scissors" state.
FIGS. 4A-4C are schematic illustrations of a TDMR read head 400 according to one embodiment. The aspects of FIGS. 3A-3D may be similar to the description of the TDMR read head 400 of FIGS. 4A-4C.
FIG. 4A is an ABS view of TDMR read head 400 according to one embodiment. The TDMR read head 400 includes a first reader including a first shield (S1) 402, a seed layer 404, a first Free Layer (FL) 406, a barrier layer 408, a second FL 410, a cap layer 412, and a second shield (S2) 422. The seed layer 404 comprises a material selected from the group consisting of tantalum, tungsten, and combinations thereof. Barrier layer 408 comprises an insulating material, such as MgO. The first reader further comprises: a first SAF SB comprising a first lower SB 416a, a first spacer 418a comprising a material such as ruthenium, and a first upper SB 420a; and a second SAF SB comprising a second lower SB 416b, a second spacer 418b comprising a material such as ruthenium, and a second upper SB 420b. The magnetic moments for the first FL 406 and the second FL 410 may be antiparallel due to an antiparallel bias from the SAF SB.
An insulated Reader Separation Gap (RSG) 424 separates the first reader and the second reader. The insulating RSG 424 may be formed of an AlOx compound or any other suitable insulating material.
The TDMR read head 400 further includes a second reader including a first shield (S1) 426, a seed layer 428, a first Free Layer (FL) 430, a barrier layer 432, a second FL 434, a cap layer 436, and a second shield (S2) 444. Seed layer 428 comprises a material selected from the group consisting of tantalum, tungsten, and combinations thereof. In one embodiment, barrier layer 432 includes MgO. The second reader further comprises: a first SAF SB comprising a first lower SB 438a, a first spacer 440a comprising a material such as ruthenium, and a first upper SB 442a; and a second SAF SB comprising a second lower SB 438b, a second spacer 440b comprising a material such as ruthenium, and a second upper SB 442b. The magnetic moments for the first FL 430 and the second FL 434 may be antiparallel due to an antiparallel bias from the SAF SB.
FIG. 4B is an APEX view of a TDMR read head 400 according to another embodiment. The first reader further includes a post hard bias (RHB) 446 and an insulator 452 behind the MTJ stack 450. Insulator 452 may be aluminum oxide (AlOx) or any other suitable insulating material. The RHB 446 generates a magnetic field directed away from the insulator 452 and toward the following layers: a first FL 406, a barrier layer 408, a second FL 410, and a cap layer 412. The RHB 446 may include cobalt platinum (CoPt) disposed on a tantalum and/or tungsten seed layer and magnetically decoupled from the second shield 422 by interposing a non-magnetic layer 462 between the RHB 446 and the second shield 422.
The second reader further includes a post hard bias (RHB) 448 and an insulator 452 behind the MTJ stack 460. Insulator 452 may be aluminum oxide (AlOx) or any other suitable insulating material. The RHB 448 generates a magnetic field that is directed away from the insulator 452 and toward the following layers: a first FL 430, a barrier layer 432, a second FL 434, and a cap layer 436. The RHB 448 may include cobalt platinum (CoPt) disposed on a tantalum and/or tungsten seed layer and magnetically decoupled from the second shield 444 by interposing a non-magnetic layer 464 between the RHB 448 and the second shield 444.
FIG. 4C is a schematic illustration of a Magnetic Tunnel Junction (MTJ) stack 450 of a TDMR read head 400 according to various embodiments. The first MTJ stack 450 of the first reader includes the seed layer 404, the first FL 406, the barrier layer 408, the second FL 410, and the cap layer 412. The second MTJ stack 460 of the second reader includes the seed layer 428, the first FL 430, the barrier layer 432, the second FL 434, and the cap layer 436.
FIG. 5 is a flowchart illustrating a method 500 of fabricating a TDMR read head according to one embodiment. Method 500 will be described in connection with the schematic illustrations of TDMR read head 600 at various stages of manufacture of FIGS. 6A-6H. The aspects of fig. 6A-6H may be similar to the components previously described above.
In fig. 6A, a lower shield 602 of a lower reader 670 is formed at block 502 (e.g., S1 of the first reader of fig. 4A). At block 504, a TMR structure is formed on the lower shield 602 of the lower reader 670. The TMR structure includes an MTJ stack including a seed layer 604, a first FL 606, a barrier layer 608, a second FL 610, and a cap layer 612. Magnetic annealing of the TMR structure may or may not be required after deposition of the TMR structure.
In FIG. 6B, SAF SB structures such as first lower SB 616a, first spacer 618a, first upper SB 620a, second lower SB 616B, second spacer 618B, and second upper SB 620B of lower reader 670 are formed at block 506. At blocks 504 and 506, the process may include mask layer deposition and photolithography, RIE etching to form a Carbon Hard Mask (CHM) template, ion etching to define the underlying MTJ, junction insulator by Atomic Layer Deposition (ALD) or Ion Beam Deposition (IBD), SB deposition, sidewall etch, resist strips, and Chemical Mechanical Polishing (CMP).
In fig. 6C, RHB structure 646 for lower reader 670 is formed via a RHB deposition process at block 508 and a nonmagnetic layer 672 is formed thereon. At block 510, the lower reader 670 is backfilled with junction insulator 652 (insulator 652). The process at block 508 and block 510 may also include photolithography, RIE etching, ion etching to define the lower MTJ trailing edge, and junction insulator 652 implemented by ALD or IBD. The junction insulator 652 may be an AlOx deposit. In one embodiment, RHB 646 includes seed layers such as Ta and W, a permanent magnet (e.g., coPt) and a non-magnetic capping layer (e.g., ta). To prevent magnet erosion during CMP and to create a topography that limits TDMR Down Track Spacing (DTS) and wire resistance, glancing angle etching is applied to planarize RHB 646. The DTS is the spacing between the first free layer 606 of the lower reader 670 and the first free layer 630 of the upper reader 680. After the cap layer 612 is deposited (e.g., ta cap), a second glancing angle etch is applied to the MTJ stack to further planarize the RHB 646. After etching occurs, resist strips and CMP are applied to achieve device surface planarization. Further, an electropolishing termination mark (electric lapping guide, ELG) may be formed during the steps outlined in blocks 508 and 510.
In fig. 6D, a top shield 622, such as the second shield 422 of fig. 4A, of the lower reader 670 is formed at block 512. At block 514, RSG 624 is formed by depositing AlOx on top shield 622 of lower reader 670. The RSG 624 may be formed by photolithography, ion etching, metal refill, or lift-off. At block 516, a lower shield 626 of an upper reader 680 is formed over the RSG 624.
In fig. 6E, a TMR structure is formed on the lower shield 626 of the upper reader 680 at block 518. The TMR structure includes an MTJ stack including a seed layer 628, a first FL 630, a barrier layer 632, a second FL 634, and a cap layer 636. Magnetic annealing is applied to the TMR structure after deposition of the TMR structure. SAF SB structures, such as first lower SB 638a, first spacer 640a, first upper SB 642a, second lower SB 638b, second spacer 640b, and second upper SB 642b of the upper DFL reader 680, are formed at block 520. At blocks 518 and 520, the process may include mask layer deposition and photolithography, RIE etching to form a Carbon Hard Mask (CHM) template, ion etching to define the underlying MTJ, junction insulator by Atomic Layer Deposition (ALD) or Ion Beam Deposition (IBD), SB deposition, sidewall etch, resist strips, and CMP.
In fig. 6F, an RHB648 for an upper reader 680 is formed at block 522 and a nonmagnetic layer 682 is formed thereon. At block 524, the upper reader 680 is backfilled with junction insulator 652 (insulator 652). The process at blocks 522 and 524 may also include photolithography, RIE etching, ion etching to define the lower MTJ trailing edge, and junction insulator 652 implemented by ALD or IBD. Furthermore, the gaps between each layer may be filled with a dielectric material that involves photolithography, alOx deposition, and lift-off. The junction insulator 652 may be an AlOx deposit. In one embodiment, RHB648 includes seed layers such as Ta and W, permanent magnets (e.g., coPt) and a non-magnetic capping layer (e.g., ta). To prevent magnet corrosion during CMP and to create a topography that limits TDMR Down Track Spacing (DTS) and wire resistance, glancing angle etching is applied to planarize RHB 648. The DTS is the spacing between the first free layer 606 of the lower reader 670 and the first free layer 630 of the upper reader 680. After the cap layer 636 is deposited, a second glancing angle etch is applied to the MTJ stack to further planarize the RHB 648. After etching occurs, resist strips and CMP are applied to achieve device surface planarization. Further, an electropolishing termination mark (ELG) may be formed during the steps outlined in block 522 and block 524. The etch depths of the upper reader 680 and the lower reader 670 determine the DTS and wire resistance of the DFL TDMR read head 600.
In fig. 6G-6H, a top shield 644 of an upper reader 680 is formed over the MTJ stack of the upper reader 680. Top shield 644 may be formed via deposition of top shield material, photocopying, nickel iron (NiFe) plating, resist strips, and ion etching. In DFL TDMR read head 600, the lower reader 670SB layer and the upper reader 680SB layer are offset antiparallel such that when the respective RHBs 646, 648 apply a magnetic field across the MTJ structures of the lower reader 670 and upper reader 680, the respective magnetic moments tilt to form a "scissors" state. Furthermore, the DFL TDMR read head 600 does not have an Antiferromagnetic (AFM) layer to anchor the Pinning Layer (PL) to the seed layer of each MTJ stack, which may result in thinner stack thickness and lower performance degradation of the MTJ.
By using a dual free layer MTJ with a SAF soft bias structure on the side and a hard bias structure behind, a TDMR head with improved reliability and ADC is achieved without causing performance degradation.
In one embodiment, a two-dimensional magnetic recording (TDMR) head includes: a first reader, comprising: a first lower shield; a first Dual Free Layer (DFL) sensor disposed over the first lower shield; and a first upper shield disposed over the first DFL sensor; an insulating reader separation gap disposed above the first reader; and a second reader disposed over the insulated reader separation gap, the second reader comprising: a second lower shield; a second DFL sensor disposed over the second lower shield; and a second upper shield disposed over the second DFL sensor. The first DFL sensor includes: a first seed layer; a first free magnetic layer disposed over the first seed layer; a first barrier layer disposed over the first free magnetic layer; a second magnetic free layer disposed over the first barrier layer; and a first capping layer disposed over the second magnetic free layer. The second DFL sensor includes: a second seed layer; a third free magnetic layer disposed over the second seed layer; a second barrier layer disposed over the third free magnetic layer; a fourth magnetic free layer disposed over the second barrier layer; and a second capping layer disposed over the fourth magnetic free layer. The TDMR head further includes a first post hard bias structure disposed behind the first DFL sensor. The TDMR head further includes a second post hard bias structure disposed behind the second DFL sensor. The TDMR head further includes at least one first Synthetic Antiferromagnetic (SAF) structure disposed adjacent to the first DFL sensor. The TDMR head further includes at least one second SAF structure disposed adjacent to the second DFL sensor. A magnetic recording apparatus including a TDMR head is also contemplated.
In another embodiment, a two-dimensional magnetic recording (TDMR) head includes: a first reader, comprising: a first lower shield; a first sensor disposed over the first lower shield; a first upper shield disposed over the first sensor; and a first rear hard bias structure disposed behind the first sensor; an insulating reader separation gap disposed above the first reader; and a second reader disposed over the insulated reader separation gap, the second reader comprising: a second lower shield; a second sensor disposed over the second lower shield; a second upper shield disposed over the second sensor; and a second rear hard bias structure disposed behind the second sensor. The first post hard bias structure comprises CoPt. The TDMR head further includes a first nonmagnetic layer disposed over the first rear hard bias structure. The TDMR head further includes an insulating material disposed between the first sensor and the first rear hard bias structure. The first sensor and the second sensor do not include an antiferromagnetic layer. A magnetic recording medium including a TDMR head is also contemplated.
In another embodiment, a two-dimensional magnetic recording (TDMR) head includes: a first reader, comprising: a first lower shield; a first sensor disposed over the first lower shield; a first upper shield disposed over the first sensor; and a first Synthetic Antiferromagnetic (SAF) Soft Bias (SB) structure disposed adjacent to the first sensor; an insulating reader separation gap disposed above the first reader; and a second reader disposed over the insulated reader separation gap, the second reader comprising: a second lower shield; a second sensor disposed over the second lower shield; a second upper shield disposed over the second sensor; and a second SAF SB structure disposed adjacent to the second sensor. The first SAF SB structure comprises: a first lower SB layer disposed over the first seed layer of the first sensor; a first spacer layer disposed over the first lower SB layer; and a first upper SB layer disposed over the first spacer. The first sensor is a first Dual Free Layer (DFL) sensor. The TDMR head further includes a first Read Hard Bias (RHB) structure disposed behind the first DFL sensor. The first sensor does not include a pinning layer. A magnetic recording medium containing a TDMR head is also contemplated.
It should be appreciated that the magnetic recording heads discussed herein are applicable to data storage devices such as Hard Disk Drives (HDDs) as well as tape drives, such as Tape Embedded Drives (TED) or pluggable tape media drives. An example TED is described in co-pending patent application serial No. 16/365,034 entitled "tape embedded drive (Tape Embedded Drive)", filed on the date 31 of 2019 and assigned to the same assignee as the present application. Any reference to an HDD or tape drive in the detailed description is for illustrative purposes only and is not intended to limit the disclosure unless explicitly required. Furthermore, references to or claims to a magnetic recording device are intended to encompass both an HDD and a tape drive unless an HDD or tape drive device is specifically required.
While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.
Claims (20)
1. A two-dimensional magnetic recording head, TDMR head, comprising:
a first reader, comprising:
a first lower shield having a first width at a media-facing surface;
a first seed layer disposed in contact with the first lower shield, the first seed layer having the first width at the media-facing surface;
a first dual free layer sensor, a first DFL sensor, disposed over the first lower shield and including a first magnetic free layer and a second magnetic free layer, the first magnetic free layer of the first dual free layer sensor disposed in contact with the first seed layer; and
a first upper shield layer disposed over and in contact with the first DFL sensor, the first upper shield layer being a single layer;
at least one first synthetic antiferromagnetic structure, a first SAF structure, disposed adjacent to the first DFL sensor, the at least one first SAF structure including a first lower soft bias layer, a first spacer layer disposed on the first lower soft bias layer, and a first upper soft bias layer disposed on the first spacer layer and in contact with the first upper shielding layer;
an insulating reader separation gap disposed above the first reader, the insulating reader separation gap disposed in contact with the first upper shield layer; and
a second reader disposed over the insulated reader separation gap, the second reader comprising:
a second lower shield that is a single layer and has the first width at the media-facing surface;
a second seed layer disposed in contact with the second lower shield, the second seed layer having the first width at the media-facing surface;
a second DFL sensor disposed over the second lower shield, the second DFL sensor aligned with the first DFL sensor at an air bearing surface, wherein a third magnetic free layer of the second DFL sensor is disposed in contact with the second seed layer; and
a second upper shield layer disposed over the second DFL sensor.
2. The TDMR head of claim 1, wherein the first DFL sensor comprises:
the first magnetic free layer disposed on the first seed layer;
a first barrier layer disposed over the first magnetic free layer;
the second magnetic free layer disposed over the first barrier layer; and
a first capping layer disposed over the second magnetic free layer.
3. The TDMR head of claim 2, wherein the second DFL sensor comprises:
the third magnetic free layer disposed over the second seed layer;
a second barrier layer disposed over the third magnetic free layer;
a fourth magnetic free layer disposed over the second barrier layer; and
a second capping layer disposed over the fourth magnetic free layer.
4. The TDMR head of claim 2, wherein the first lower soft bias layer is disposed adjacent to a portion of the first magnetic free layer and a portion of the first barrier layer, the first spacer layer is disposed adjacent to a portion of the first barrier layer and a portion of the second magnetic free layer, and the first upper soft bias layer is disposed adjacent to a portion of the second magnetic free layer and the first capping layer.
5. The TDMR head of claim 1, further comprising a first post hard bias structure disposed behind the first DFL sensor.
6. The TDMR head of claim 5, further comprising a second post hard bias structure disposed behind the second DFL sensor.
7. The TDMR head of claim 1, further comprising at least one second SAF structure disposed adjacent to the second DFL sensor.
8. A magnetic recording apparatus comprising the TDMR head of claim 1.
9. A two-dimensional magnetic recording head, TDMR head, comprising:
a first reader, comprising:
a first lower shield having a first width at a media-facing surface;
a first seed layer disposed in contact with the first lower shield, the first seed layer having the first width at the media-facing surface;
a first sensor disposed over the first lower shield, a first magnetic free layer of the first sensor disposed in contact with the first seed layer;
a first upper shield layer disposed over and in contact with the first sensor; and
a first rear hard bias structure disposed behind the first sensor;
at least one first synthetic antiferromagnetic structure, a first SAF structure, disposed adjacent to the first sensor, the at least one first SAF structure comprising a first lower soft bias layer, a first spacer layer disposed on the first lower soft bias layer, and a first upper soft bias layer disposed on the first spacer layer and in contact with the first upper shield layer;
an insulating reader separation gap disposed above the first reader, the insulating reader separation gap disposed in contact with the first upper shield layer; and
a second reader disposed over the insulated reader separation gap, the second reader comprising:
a second lower shield that is a single layer and has the first width at the media-facing surface;
a second seed layer disposed in contact with the second lower shield, the second seed layer having the first width at the media-facing surface;
a second sensor disposed over the second lower shield, the second sensor aligned with the first sensor at an air bearing surface, wherein a first magnetic free layer of the second sensor is disposed in contact with the second seed layer;
a second upper shield layer disposed over the second sensor, the second upper shield layer being a single layer; and
a second rear hard bias structure disposed behind the second sensor.
10. The TDMR head of claim 9, wherein the first post hard bias structure comprises CoPt.
11. The TDMR head of claim 9, further comprising a first nonmagnetic layer disposed over the first post-hard bias structure.
12. The TDMR head of claim 9, further comprising an insulating material disposed between the first sensor and the first post hard bias structure.
13. The TDMR head of claim 9, wherein the first sensor and the second sensor do not include antiferromagnetic layers.
14. The TDMR head of claim 9, wherein the first lower shield has a first length from the media-facing surface into the TDMR head, the first seed layer has the first length from the media-facing surface into the TDMR head, the second lower shield has the first length from the media-facing surface into the TDMR head, and the second seed layer has the first length from the media-facing surface into the TDMR head.
15. A magnetic recording apparatus comprising the TDMR head of claim 9.
16. A two-dimensional magnetic recording head, TDMR head, comprising:
a first reader, comprising:
a first lower shield that is a single layer and has a first width at a media-facing surface;
a first seed layer disposed in contact with the first lower shield, the first seed layer having the first width at the media-facing surface;
a first sensor disposed over the first lower shield, a first magnetic free layer of the first sensor disposed in contact with the first seed layer;
a first upper shield layer disposed over and in contact with the first sensor, the first upper shield layer being a single layer; and
a first synthetic antiferromagnetic soft bias structure, a first SAF SB structure, disposed adjacent to the first sensor, the first SAF SB structure comprising a first lower soft bias layer, a first spacer layer disposed on the first lower soft bias layer, and a first upper soft bias layer disposed on the first spacer layer and in contact with the first upper shield layer;
an insulating reader separation gap disposed above the first reader, the insulating reader separation gap disposed in contact with the first upper shield layer; and
a second reader disposed over the insulated reader separation gap, the second reader comprising:
a second lower shield having the first width at the media-facing surface;
a second seed layer disposed in contact with the second lower shield, the second seed layer having the first width at the media-facing surface;
a second sensor disposed over the second lower shield, the second sensor aligned with the first sensor at an air bearing surface, wherein a first magnetic free layer of the second sensor is disposed in contact with the second seed layer;
a second upper shield layer disposed over the second sensor; and
a second SAF SB structure disposed adjacent to the second sensor, the second SAF SB structure comprising a second lower soft bias layer, a second spacer layer disposed on the second lower soft bias layer, and a second upper soft bias layer disposed on the second spacer layer and in contact with the second upper shield layer.
17. The TDMR head of claim 16, wherein the first sensor is a first dual free layer sensor or a first DFL sensor.
18. The TDMR head of claim 17, further comprising a first post hard bias (RHB) structure disposed behind the first DFL sensor.
19. The TDMR head of claim 16, wherein the first sensor does not include a pinning layer.
20. A magnetic recording device comprising the TDMR head of claim 16.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US16/899,366 US11410690B2 (en) | 2020-06-11 | 2020-06-11 | Two-dimensional magnetic recording reader with dual free layer magnetic tunnel junction |
| US16/899,366 | 2020-06-11 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN113808625A CN113808625A (en) | 2021-12-17 |
| CN113808625B true CN113808625B (en) | 2023-09-19 |
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