Magnetic read sensor with stable upper reader and related methods

Abstract

Aspects of the present disclosure generally relate to magnetic recording heads of magnetic recording devices. A read head includes a first reader, an insulating separation layer, and a second reader disposed above the insulating separation layer. The second reader includes a magnetic seed layer and a cap layer. The second reader includes a first upper free layer disposed between the magnetic seed layer and the cap layer, and a second upper free layer disposed between the first upper free layer and the cap layer. The second reader includes a barrier layer. In one embodiment, the second reader includes an anti-ferromagnetic (AFM) layer disposed between the magnetic seed layer and the insulating separation layer to pin the magnetic seed layer.

Description

TECHNICAL FIELD

[0001] Aspects of the present disclosure generally relate to magnetic recording heads of magnetic recording devices, such as magnetic read sensors of magnetic read heads of hard disk drives (HDDs). BACKGROUND

[0002] At the core of the functionality and capability of computers is the storing and writing of data to data storage devices, such as hard disk drives (HDDs). The amount of data processed by computers is rapidly increasing. Higher recording densities of magnetic recording media are needed to increase the functionality and capability of computers.

[0003] To achieve higher recording densities, such as recording densities of more than 2 Tbit / in 2 of magnetic recording media, the width and pitch of written tracks are narrowed, and thus the corresponding magnetic recording bits encoded in each written track are narrowed. Attempts have been made to implement increasingly demanding requirements of advanced narrow gap reader sensors of read heads to achieve higher recording densities.

[0004] However, attempts to shrink reader sensor dimensions, shrink reader-to-reader spacing, and increase recording densities can result in reader sensor instability and can result in sensor failure. For example, two-dimensional magnetic recording (TDMR) can be used to improve areal density capability (ADC) and read performance, but can involve instability of the sensor. Instability can worsen as the dimensions of TDMR devices are narrowed.

[0005] Accordingly, there is a need in the art for improved magnetic read heads that facilitate enhanced reader resolution performance while facilitating stability of the reader. SUMMARY

[0006] Aspects of the present disclosure generally relate to magnetic recording heads of magnetic recording devices. The read head includes a first reader, an insulating separation layer, and a second reader disposed above the insulating separation layer. The second reader includes a magnetic seed layer and a cap layer. The second reader includes a first upper free layer disposed between the magnetic seed layer and the cap layer, and a second upper free layer disposed between the first upper free layer and the cap layer. The second reader includes a barrier layer. In one embodiment, the second reader includes an anti-ferromagnetic (AFM) layer disposed between the magnetic seed layer and the insulating separation layer to pin the magnetic seed layer. In one embodiment, the first reader includes a lower shield, a second shield, and a first anti-ferromagnetic (AFM) layer disposed above the second shield; and the second reader includes a second AFM layer disposed between the magnetic seed layer and the insulating separation layer to pin the magnetic seed layer, and a third AFM layer disposed above an upper shield of the second reader.

[0007] In one embodiment, a read head for a magnetic recording device includes a first reader. The first reader includes a lower shield, a first lower free layer disposed above the lower shield, a second lower free layer disposed above the first lower free layer, and a second shield disposed above the second lower free layer. The read head includes an insulating separation layer disposed above the first reader. The read head includes a second reader. The second reader includes a magnetic seed layer disposed above the insulating separation layer, and an antiferromagnetic (AFM) layer disposed between the magnetic seed layer and the insulating separation layer to pin the magnetic seed layer. The second reader includes a cap layer, a first upper free layer disposed between the magnetic seed layer and the cap layer, and a second upper free layer disposed between the first upper free layer and the cap layer. The second reader includes a barrier layer disposed between the first upper free layer and the second upper free layer, and an upper shield disposed above the cap layer.

[0008] In one embodiment, a read head for a magnetic recording device includes a first reader. The first reader includes a lower shield, a magnetic seed layer disposed above the lower shield, and a first lower free layer disposed above the magnetic seed layer. The first reader includes a second lower free layer disposed above the first lower free layer and a second shield disposed above the second lower free layer. The first reader includes a first antiferromagnetic (AFM) layer disposed above the second shield. The read head includes an insulating separation layer disposed above the first AFM layer. The read head includes a second reader. The second reader includes a magnetic seed layer disposed above the insulating separation layer, a second AFM layer disposed between the magnetic seed layer of the second reader and the insulating separation layer to pin the magnetic seed layer of the second reader. The second reader includes a cap layer. The second reader includes a first upper free layer disposed between the magnetic seed layer and the cap layer of the second reader, a second upper free layer disposed between the first upper free layer and the cap layer, and an upper shield disposed above the cap layer.

[0009] In one embodiment, a read head for a magnetic recording device includes a first reader. The first reader includes a lower shield, a first lower free layer disposed above the lower shield, and a second lower free layer disposed above the first lower free layer. The first reader includes a second shield disposed above the second lower free layer. The read head includes an insulating separation layer disposed above the first reader. The read head includes a second reader. The second reader includes a magnetic seed layer disposed above the insulating separation layer, a first ferromagnetic (FM) layer disposed between the insulating separation layer and the magnetic seed layer, and a second FM layer disposed between the first FM layer and the magnetic seed layer. The first FM layer and the second FM layer are magnetized antiparallel to each other. The second reader includes a nonmagnetic spacer layer disposed between the first FM layer and the second FM layer. The nonmagnetic spacer layer is formed of ruthenium (Ru). The second reader includes a cap layer, a first upper free layer disposed between the magnetic seed layer and the cap layer, a second upper free layer disposed between the first upper free layer and the cap layer, and an upper shield disposed above the cap layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] In order that the above-recited features of the present disclosure may be understood in detail, a more particular description of the present disclosure, briefly summarized above, may be made by reference to embodiments, some of which are illustrated in the accompanying drawings. It is noted, however, that the drawings illustrate only typical embodiments of the present disclosure and are therefore not to be considered limiting of the scope of the present disclosure, as the disclosure may admit to other equally effective embodiments.

[0011] Figure 1 is a schematic diagram of a magnetic media drive having a magnetic write head and a magnetic read head according to one embodiment.

[0012] Figure 2 is a schematic cross-sectional side view of a magnetic head assembly facing a magnetic disk or magnetic storage media according to one embodiment.

[0013] Figure 3 is a schematic MFS view of a read head according to one embodiment.

[0014] Figure 4 According to one embodiment Figure 3 Schematic cross-sectional side view of the read head shown in .

[0015] Figure 5 According to one embodiment Figure 3 Schematic isometric view of the read head shown in .

[0016] Figure 6 is a schematic MFS view of a read head according to one embodiment.

[0017] Figure 7 is a schematic MFS view of a read head according to one embodiment.

[0018] Figure 8 is a schematic MFS view of a read head according to one embodiment.

[0019] Figure 9 is a schematic graphical illustration of a graph showing expected failure rates according to one embodiment.

[0020] Figure 10-12 are schematic graphical views of the figures, respectively illustrating a tested reader linear resolution, a tested signal-to-noise ratio (SNR), and a tested areal density capability (ADC), according to one embodiment.

[0021] 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

[0022] In the following, reference is made to embodiments of the present disclosure. However, it should be understood that the present disclosure is not limited to the specifically described embodiments. Instead, any combination of the following features and elements, whether or not with respect to different embodiments, is intended to constitute and practice the present disclosure. In addition, although embodiments of the present disclosure may achieve advantages over other possible solutions and / or over the prior art, whether or not a particular advantage is achieved by a given embodiment does not limit the present disclosure. Therefore, the following aspects, features, embodiments and advantages are merely illustrative and are not considered to be elements or limitations of the appended claims, except to the extent expressly recited in the claims. Likewise, reference to the "present disclosure" should not be interpreted as a generalization of any inventive subject matter disclosed herein and should not be considered to be elements or limitations of the appended claims, except to the extent expressly recited in the claims.

[0023] Aspects of the present disclosure generally relate to a magnetic recording head of a magnetic recording device. The read head includes a first reader, an insulating separation layer, and a second reader disposed above the insulating separation layer. The second reader includes a magnetic seed layer and a cap layer. The second reader includes a first upper free layer disposed between the magnetic seed layer and the cap layer, and a second upper free layer disposed between the first upper free layer and the cap layer. The second reader includes a barrier layer. In one embodiment, the second reader includes an antiferromagnetic (AFM) layer disposed between the magnetic seed layer and the insulating separation layer to pin the magnetic seed layer. In one embodiment, the first reader includes a lower shield, a second shield, and a first antiferromagnetic (AFM) layer disposed above the second shield; and the second reader includes a second AFM layer disposed between the magnetic seed layer and the insulating separation layer to pin the magnetic seed layer, and a third AFM layer disposed above the upper shield of the second reader.

[0024] It should be understood that the magnetic recording heads discussed herein may be applied to data storage devices such as hard disk drives (HDDs), as well as tape drives such as tape embedded drives (TEDs) or drives that can be inserted into tape media. An example TED is described in co-pending U.S. patent application Ser. No. 16 / 365,034, filed Mar. 31, 2019, entitled "Tape Embedded Drive," which is assigned to the same assignee as the present application and is incorporated herein by reference. Therefore, any reference to an HDD or tape drive in the detailed description is for exemplary purposes only and is not intended to limit the present disclosure unless expressly stated otherwise. Furthermore, references to or claims directed to a magnetic recording device are intended to include both HDDs and tape drives unless an HDD or tape drive device is expressly stated otherwise.

[0025] It should also be understood that aspects disclosed herein (such as magnetoresistive devices) can be used in magnetic sensor applications other than HDDs and tape media drives (such as TEDs), such as spintronic devices other than HDDs and tape media drives. As an example, aspects disclosed herein can be used in magnetoresistive random access memory (MRAM) devices (e.g., magnetic tunnel junctions as part of a memory element), magnetic sensors, or magnetic elements in other spintronic devices. It should be noted that while the terms "reader" or "read head" are used to describe the various embodiments shown below, those skilled in the art will recognize that the disclosed stacks and structures can be considered sensors or magnetic tunnel junctions, or portions of sensors or magnetic tunnel junctions. Therefore, the scope of the present disclosure is intended to encompass those embodiments as well.

[0026] Figure 1 FIG2 is a schematic diagram of a magnetic media drive 100 having a magnetic write head and a magnetic read head according to one embodiment. The magnetic media drive 100 can be a single drive / device or can include multiple drives / devices. The magnetic media drive 100 includes a magnetic recording medium, such as one or more rotatable magnetic disks 112 supported on a shaft 114 and rotated by a drive motor 118. For ease of illustration, a single disk drive is shown according to one embodiment. The magnetic recording on each disk 112 is in the form of any suitable pattern of data tracks, such as an annular pattern of concentric data tracks (not shown) on the disks 112.

[0027] 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 having a two-dimensional magnetic recording (TDMR) device. As the magnetic disk 112 rotates, the slider 113 moves radially in and out over the disk surface 122 so that the head assembly 121 can access different tracks of the magnetic disk 112 to write or read desired data. Each slider 113 is attached to an actuator arm 119 by a suspension 115. The suspension 115 provides a slight spring force that biases the slider 113 toward the disk surface 122. Each actuator arm 119 is attached to an actuator 127. As Figure 1 The actuator 127 shown may be a voice coil motor (VCM). A VCM comprises a coil that is movable within a fixed magnetic field. A motor current signal supplied by a control unit 129 controls the direction and speed of movement of the coil.

[0028] During operation of magnetic media drive 100, the rotation of magnetic disk 112 creates an air or gas bearing between slider 113 and disk surface 122 that exerts an upward force or lift on slider 113. The air or gas bearing thus counterbalances 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.

[0029] The various components of the magnetic media drive 100 are controlled in operation by control signals (such as access control signals and internal clock signals) generated by a control unit 129. Typically, the control unit 129 includes logic control circuitry, storage components, and a microprocessor. The control unit 129 generates control signals for controlling 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 the slider 113 to the desired data track on the disk 112. Write and read signals are communicated to and from the head assembly 121 via the recording channel 125. Figure 1 The magnetic media drive 100 may include multiple media (or disks), multiple actuators, and / or multiple sliders.

[0030] Figure 2 FIG. 2 is a schematic cross-sectional side view of a magnetic head assembly 200 facing a magnetic disk 112 or other magnetic storage medium according to one embodiment. The magnetic head assembly 200 may correspond to or be used as Figure 1 The head assembly 121 is shown in FIG. The head assembly 200 includes a medium facing surface (MFS) 212 such as an air bearing surface (ABS) that faces the magnetic disk 112. Figure 2 As shown, the magnetic disk 112 relatively moves in the direction indicated by arrow 232 , and the head assembly 200 relatively moves in the direction indicated by arrow 233 .

[0031] Magnetic head assembly 200 includes a magnetic read head 211. 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 the surfaces of shields S1, S2, and S3 are all located at MFS 212 facing magnetic disk 112. In one embodiment that can be combined with other embodiments, sensing elements 204a, 204b are TDMR devices that sense the magnetic field of a recorded bit (such as a perpendicular or longitudinal recorded bit) in magnetic disk 112 using the TDMR effect. In one embodiment that can be combined with other embodiments, the spacing between shields S1 and S2 and the spacing between shields S2 and S3 are approximately 17 nm or less.

[0032] The magnetic head assembly 200 may include a write head 210. The write head 210 includes a main pole 220, a front shield 206, and a trailing shield (TS) 240. The main pole 220 includes a magnetic material and serves as a main electrode. The front portion of each of the main pole 220, the front shield 206, and the TS 240 is at the MFS 212. The write head 210 includes a coil 218 surrounding the main pole 220, which excites the main pole 220 to generate a write magnetic field to affect the magnetic recording medium of the rotatable disk 112. The coil 218 can be a spiral structure or a set of one or more flat structures. The TS 240 includes a magnetic material and serves as a return pole for the main pole 220. The front shield 206 can provide electromagnetic shielding and is separated from the main pole 220 by a front gap 254.

[0033] Figure 3 is a schematic MFS view of a read head 300 according to one embodiment. The read head 300 may be such as Figure 1 The magnetic recording device portion of the magnetic media drive 100 is shown.

[0034] The read head 300 includes a first reader 310, a second reader 320 disposed above the first reader 310 in the along-track direction, and an insulating separation layer 319 disposed above the first reader 310 and below the second reader 320. The insulating separation layer 319 is disposed between the first reader 310 and the second reader 320. The first reader 310 includes a lower shield 311, a first lower free layer 314 disposed above the lower shield 311, and a second lower free layer 316 disposed above the first lower free layer 314. The first reader 310 includes a second shield 318 disposed above the second lower free layer 316.

[0035] The second reader 320 includes a magnetic seed layer 323 disposed above the insulating separation layer 319 and an antiferromagnetic (AFM) layer 322 disposed between the magnetic seed layer 323 and the insulating separation layer 319 to pin the magnetic seed layer 323. The second reader 320 includes a cap layer 328, a first upper free layer 325 disposed between the magnetic seed layer 323 and the cap layer 328, and a second upper free layer 327 disposed between the first upper free layer 325 and the cap layer 328. The second reader 320 includes a barrier layer 326 disposed between the first upper free layer 325 and the second upper free layer 327, and an upper shield 329 disposed above the cap layer 328. The second reader 320 includes a nonmagnetic spacer layer 321 disposed between the insulating separation layer 319 and the AFM layer 322. The nonmagnetic spacer layer 321 may be omitted so that the insulating separation layer 319 contacts the AFM layer 322. A thickness T2 may be added to the thickness of the insulating separation layer 319. The non-magnetic seed layer 324 is disposed between the first upper free layer 325 and the magnetic seed layer 323 .

[0036] The second reader 320 includes a plurality of first soft bias side shields 331a, 331b disposed above the magnetic seed layer 323, and a plurality of second soft bias side shields 332a, 332b disposed above the plurality of first soft bias side shields 331a, 331b. The second reader 320 includes a plurality of spacer layers 333a, 333b between the plurality of soft bias side shields 331a, 332a and the plurality of soft bias side shields 331b, 332b, respectively. An insulating material 334 is disposed between layers 323-328 and layers 331a-332b. The second reader 320 includes a thin dusting layer 339 disposed between the AFM layer 322 and the magnetic seed layer 323. The second reader 320 includes an AFM layer 342 disposed above the upper shield 329. About Figure 3 In the illustrated embodiment, the AFM layer 342 is a second AFM layer.

[0037] The first reader 310 includes a magnetic seed layer 312 disposed above a lower shield 311 and a non-magnetic seed layer 313 disposed above the magnetic seed layer 312. The first reader 310 includes a cap layer 317. A first lower free layer 314 is disposed between the magnetic seed layer 312 and the cap layer 317. A second lower free layer 316 is disposed between the first lower free layer 314 and the cap layer 317. The first reader 310 includes a barrier layer 315 disposed between the first lower free layer 314 and the second lower free layer 316.

[0038] The first reader 310 includes a plurality of first soft bias side shields 335a, 335b disposed above the magnetic seed layer 312, and a plurality of second soft bias side shields 336a, 336b disposed above the plurality of first soft bias side shields 335a, 335b. The first reader 310 includes a plurality of spacer layers 337a, 337b disposed between the plurality of soft bias side shields 335a, 336a and the plurality of soft bias side shields 335b, 336b, respectively. An insulating material 338 is disposed between the layers 312-317 and the layers 335a-336b.

[0039] The dustproof layer 339 of the second reader 320 is formed of one or more of ruthenium (Ru) and / or cobalt iron (CoFe). The dustproof layer 339 has a thickness T1 along the track direction. Thickness T1 is 1 nm or less. The cap layers 317 and 328 are non-ferromagnetic. The cap layers 317 and 328 are formed of one or more of tantalum (Ta), titanium (Ti), ruthenium (Ru), and / or cobalt hafnium (CoHf). Each of the cap layers 317 and 328 may include a multilayer structure having layers formed of one or more of tantalum (Ta), titanium (Ti), ruthenium (Ru), and / or cobalt hafnium (CoHf). The free layers 314, 316, 325, and 327 are ferromagnetic. The free layers 314, 316, 325, and 327 are formed of one or more of cobalt (Co), iron (Fe), boron (B), nickel (Ni), and / or hafnium (Hf). Barrier layers 315 and 326 are formed of MgO. Insulating materials 334 and 338 and insulating separation layer 319 are each formed of aluminum oxide (AlOx), magnesium oxide (MgO), and / or other suitable insulating materials. Non-magnetic spacer layer 321 is formed of ruthenium (Ru), chromium ruthenium (CrRu), or nickel chromium (NiCr). The non-magnetic spacer layer has a thickness T2 along the track direction. Thickness T2 is 2 nm or greater. AFM layer 322 has a thickness T3 along the track direction. Thickness T3 is in the range of 3 nm to 8 nm. The magnetic seed layer 323 of the second reader 320 includes a platform 341 protruding in the track direction. The upper surface 365 of the platform 341 is set at a distance D1 relative to the AFM layer 322. Distance D1 is 10 nm or greater, for example, in the range of 10 nm to 30 nm. In one embodiment that can be combined with other embodiments, distance D1 is in the range of 10 nm to 20 nm.

[0040] The magnetic seed layers 312, 323 and the non-magnetic seed layers 313, 324 are each formed of one or more of nickel iron (NiFe), cobalt iron (CoFe), (cobalt boron) CoB, cobalt iron boron (CoFeB), and / or cobalt hafnium (CoHf). Other materials may be used for the seed layers 312, 313, 323, 324. The lower shield 311 has a thickness T4 along the track direction. The thickness T4 is 100 nm or greater. The spacer layers 333a, 333b are formed of ruthenium (Ru). The first and second soft bias side shields 331a-331b, 332a-332b, 335a-335b, 336a-335b are magnetic and conductive. The first and second soft-bias side shields 331a-331b, 332a-332b, 335a-335b, 336a-335b are formed of nickel iron (NiFe) and / or CoFe. The second shield 318 has a thickness T5 along the track direction. Thickness T5 is less than 40 nm. An optional non-magnetic layer 343 is disposed between the lower shield 311 and the magnetic seed layer 312. The non-magnetic layer 343 is formed of one or more of cobalt boron (CoB), cobalt hafnium (CoHf), ​​titanium (Ti), chromium (Cr), and / or nickel chromium (NiCr). The non-magnetic layer 343 has a thickness T7 along the track direction. Thickness T7 is 2 nm or greater.

[0041] The AFM layer 322 pins the magnetic seed layer 323 of the second reader 320. The AFM layer 322, the magnetic seed layer 323, the second upper free layer 327, the AFM layer 342, the upper shield 329, the second shield 318, and the plurality of second soft-bias side shields 332a, 332b, 336a, 336b are magnetized in the same magnetization direction, as indicated by magnetization arrows M1, M2, M4-M8, and M19. The second upper free layer 327 is magnetized antiparallel to the first upper free layer 325, as indicated by magnetization arrow M8. Figure 3 Shields 311, 318, and 329 are each formed from one or more of nickel iron (NiFe), cobalt iron (CoFe), (cobalt boron) CoB, cobalt iron boron (CoFeB), and / or cobalt hafnium (CoHf). Other materials may be used for shields 311, 318, and 329.

[0042] The AFM layer 322 and the dust layer 339 help to pin the magnetic seed layer 323. In one embodiment that can be combined with other embodiments, the pinning strength of the magnetic seed layer 323 is 0.1 erg / cm 2 to 0.4 erg / cm 2 within the range.

[0043] Figure 4 According to one embodiment Figure 3A schematic cross-sectional side view of the read head 300 is shown in FIG. Figure 4 Cross-sectional hatching is not shown. The first reader 310 includes a first back hard bias layer 345 disposed behind layers 313-317 along the stripe height direction, and the second reader 320 includes a second back hard bias layer 346 disposed behind layers 324-328 along the stripe height direction. The first back hard bias layer 345 and the second back hard bias layer 346 are formed of cobalt platinum (CoPt) with an appropriate seed layer.

[0044] Figure 5 According to one embodiment Figure 3 A schematic isometric view of a readhead 300 is shown in FIG.

[0045] Figure 6 is a schematic MFS view of a read head 600 according to one embodiment. The read head 600 may be such as Figure 1 The magnetic recording device portion of the magnetic media drive 100 is shown. The read head 600 is similar to Figure 3 3 and includes one or more of its aspects, features, components, and / or properties. As an example, read head 600 includes layers 323-328 and first and second soft bias side shields 331a-332b.

[0046] The first reader 610 of the read head 600 includes an AFM layer 609 disposed above the second shield 318. The AFM layer 609 is disposed between the second shield 318 and the insulating separation layer 319. Figure 6 In the illustrated embodiment, AFM layer 609 is the first AFM layer, AFM layer 322 is the second AFM layer, and AFM layer 342 is the third AFM layer. The magnetic seed layer 312 of the first reader 310 includes a platform 367 protruding in the along-track direction. The upper surface 368 of the platform 367 is positioned at a distance D2 relative to the lower shield 311. Distance D2 is 100 angstroms or greater. In one embodiment that may be combined with other embodiments, distance D2 is in the range of 100 to 200 angstroms.

[0047] Each of the first AFM layer 609, the second AFM layer 322, and the third AFM layer 342 is magnetized in the same magnetization direction, as indicated by magnetization arrows M1, M5, and M9. Each of the first AFM layer 609, the second AFM layer 322, and the third AFM layer 342 is magnetic and conductive. Each of the first AFM layer 609, the second AFM layer 322, and the third AFM layer 342 is formed of iridium manganese (IrMn).

[0048] Also disclosed is a method of manufacturing a read head. Figure 6In the method of the read head 600 shown, the second shield 318, layer 609 and layers 319, 322-328 are deposited on the cap layer 317 and the second soft bias side shields 336a, 336b. The layers 323-328 are then milled to form Figure 6 341). Layers 331a-333b, a second post-hard bias layer 346, and insulating material 334 are then deposited. An upper shield 329 and a third AFM layer 342 are then deposited. After depositing the upper shield 329 and the third AFM layer 342, a cooling operation is performed on the read head 600 in the longitudinal field direction LD1. The cooling operation includes heating the read head 600 to above the Neel temperature of the AFM layers 322, 342, and 609 and allowing the read head 600 to cool to room temperature. The cooling operation helps establish the magnetization of the read head 600 (e.g., as shown by magnetization arrows M1, M2, M3-M5, M9, and M19) in a single cooling operation. The cooling operation helps reduce operational delays and improve cost efficiency.

[0049] Figure 7 is a schematic MFS view of a read head 700 according to one embodiment. The read head 700 may be such as Figure 1 The magnetic recording device portion of the magnetic media drive 100 is shown. The reading head 700 is similar to Figure 6 6 and includes one or more of its aspects, features, components and / or properties. As an example, the read head 700 includes layers 323-328 and first and second soft bias side shields 331a-332b. The read head 700 is similar to Figure 3 3 and includes one or more of its aspects, features, components, and / or properties. As an example, the read head 700 includes a non-magnetic spacer layer 321 .

[0050] The second reader 720 of the read head 700 includes a first ferromagnetic (FM) layer 709 disposed between the insulating separation layer 319 and the magnetic seed layer 323, and a second FM layer 722 disposed between the first FM layer 709 and the magnetic seed layer 323. The first FM layer 709 and the second FM layer 722 are magnetized antiparallel to each other, as shown in FIG. Figure 7 As shown by the magnetization arrows M16 and M17. Figure 7 In the embodiment shown, the non-magnetic spacer layer 321 is disposed between the first FM layer 709 and the second FM layer 722. Figure 7 In the illustrated embodiment, the nonmagnetic spacer layer 321 is formed of ruthenium (Ru).

[0051] The first FM layer 709, the nonmagnetic spacer layer 321, and the second FM layer 722 are part of a synthetic antiferromagnetic (SAF) structure that helps stabilize the magnetic seed layer 323 of the second reader 720. The SAF structure helps induce a large spin flip field, which helps stabilize the magnetic seed layer 323.

[0052] Figure 8 is a schematic MFS view of a read head 800 according to one embodiment. The read head 800 may be a Figure 1 The magnetic recording device portion of the magnetic media drive 100 is shown. The reading head 800 is similar to Figure 7 7 and includes one or more of its aspects, features, components, and / or properties. As an example, read head 800 includes layers 324-328, first and second soft bias side shields 331a-332b, and non-magnetic spacer layer 321.

[0053] The second reader 820 of the read head 800 includes a first FM layer 819 (which is similar to Figure 7 The second reader 820 includes a second FM layer 822 (which is similar to the first FM layer 709 shown in FIG. 1 ) and an antiferromagnetic (AFM) layer 809 between the insulating separation layer 319. The AFM layer 809 is magnetic and conductive. Figure 7 The second FM layer 722 shown) and the magnetic seed layer 823 (which is similar to Figure 7 ). The AFM layer 809 is formed of iridium manganese (IrMn).

[0054] The AFM layer 809, the magnetic seed layer 823, the second upper free layer 327, the upper shield 329, the plurality of second soft bias side shields 332a, 332b, the plurality of second soft bias side shields 336a, 336b, the second shield 318 and the lower shield 311 are magnetized in the same magnetization direction, as shown in FIG. Figure 8 The first FM layer 819 is magnetized in the same magnetization direction as the AFM layer 809, as indicated by magnetization arrows M4, M6, M7, M8, and M18-M22. The second FM layer 822 and the magnetic seed layer 823 are magnetized in the same magnetization direction as the first upper free layer 325, as indicated by magnetization arrows M3, M24, and M25.

[0055] exist Figure 8 In the illustrated embodiment, the SAF structure helps pin the magnetic seed layer 823 to stabilize the magnetic seed layer 823. The AFM layer 809 helps further pin and stabilize the magnetic seed layer 823.

[0056] Figure 9is a schematic graphical representation of a graph 900 illustrating tested failure rates, according to one embodiment. The Y-axis of graph 900 illustrates the failure rate of a second reader (e.g., the upper reader) of the read head. The X-axis of graph 900 illustrates the external longitudinal field stress applied to the read head. A first curve 910 was plotted using a read head having aspects disclosed herein, such as a magnetic seed layer 323 for the second reader 320. A second curve 920 was plotted using a read head having a configuration different from that of first curve 910. Graph 900 demonstrates that first curve 910 exhibits greater stability and lower failure rates under various external field stresses. Using aspects of the disclosure described herein, it is believed that the failure rate can be reduced by approximately 76% or more, for example, by approximately 83% or more. It is believed that pinning the magnetic seed layer 323 to promote magnetization arrow M2 facilitates achieving this reduction in failure rate.

[0057] As an example, it is believed that the stability of the magnetic seed layer 323 to L-field disturbances during read / write operations is enhanced. Using aspects of the present disclosure, the two free layers 325, 327 can be used to help increase the areal density capability (ADC) of the second reader 320 to enhance the reader linear resolution performance, while also helping to enhance the stability (e.g., L-field robustness) of the magnetic seed layer 323 and the second reader 320. For example, when magnetic interaction occurs between the magnetic seed layer 323 (such as the land 341) and the second post-hard bias layer 346, and when the structure is formed adjacent to the land 341, the stability of the second reader 320 is facilitated.

[0058] Figure 10-12 1 is a schematic graphical representation of graphs 1000, 1100, and 1200, respectively, illustrating tested reader linear resolution, tested signal-to-noise ratio (SNR), and tested areal density capability (ADC), according to one embodiment. Graphs 1000, 1100, and 1200 illustrate data from a test of a second reader (e.g., an upper reader) of the readhead.

[0059] Curves 1001, 1101, and 1201 of graphs 1000, 1100, and 1200 were created using a read head having aspects disclosed herein, such as the magnetic seed layer 323 for the second reader 320. Curves 1001, 1101, and 1201 illustrate linear resolution, SNR, and ADC, respectively, across multiple values ​​of AFM pinning strength Jk. Graphs 1000, 1100, and 1200 illustrate that at weak pinning (illustrated by lower Jk values), resolution increases while SNR may decrease. Using aspects disclosed herein, other configurations of the upper reader, such as the magnetic seed layer 323, may be more accurate than those without using aspects disclosed herein to stabilize the upper reader. Figure 10-12There may be an optimum region (such as in the Jk range of 0.2 to 0.35) for a higher ADC with a lower pinning strength than the ADC with a higher coupling region (as shown in FIG. 1 ). Using the aspects described herein facilitates such benefits.

[0060] Benefits of the present disclosure include enhanced reader linear resolution performance and enhanced ADC for higher density recording, enhanced squeezability, beneficial skirt ratio, mitigated signal-to-noise ratio (SNR) loss, use of two free layers 325, 327 with narrow shield-to-shield spacing, narrow spacing between the magnetic seed layer 323 and the upper shield 329, reduced operational delays, improved cost efficiency, decoupling the second shield 318 from the sensor stack of the second reader 320, and enhanced reader stability (such as L-field robustness of the magnetic seed layer 323).

[0061] It is contemplated that one or more aspects disclosed herein may be combined. As an example, the present disclosure contemplates that aspects of readhead 300, readhead 600, readhead 700, and / or readhead 800 may be combined. Furthermore, it is contemplated that one or more aspects disclosed herein may include some or all of the benefits described above.

[0062] In one embodiment, a read head for a magnetic recording device includes a first reader. The first reader includes a lower shield, a first lower free layer disposed above the lower shield, a second lower free layer disposed above the first lower free layer, and a second shield disposed above the second lower free layer. The read head includes an insulating separation layer disposed above the first reader, and a second reader. The second reader includes a magnetic seed layer disposed above the insulating separation layer, and an antiferromagnetic (AFM) layer disposed between the magnetic seed layer and the insulating separation layer to pin the magnetic seed layer. The second reader includes a cap layer, a first upper free layer disposed between the magnetic seed layer and the cap layer, and a second upper free layer disposed between the first upper free layer and the cap layer. The second reader includes a barrier layer disposed between the first upper free layer and the second upper free layer, and an upper shield disposed above the cap layer. The AFM layer has a thickness in a direction along the track. The thickness is in a range of 3 nm to 8 nm. The second reader includes a dust layer disposed between the AFM layer and the magnetic seed layer. The dust layer is formed of one or more of ruthenium (Ru) or cobalt iron (CoFe). The thickness of the dust layer is 1 nm or less. The second reader includes a non-magnetic spacer layer disposed between the AFM layer and the insulating separation layer. The non-magnetic spacer layer has a thickness of 2 nm or greater. The magnetic seed layer includes a platform protruding in the direction of the magnetic track. The upper surface of the platform is disposed at a distance relative to the AFM layer, and the distance is in the range of 10 nm to 30 nm. The second reader includes a plurality of first soft-bias side shields disposed above the magnetic seed layer, a plurality of second soft-bias side shields disposed above the plurality of first soft-bias side shields, and a plurality of spacer layers between the plurality of first soft-bias side shields and the plurality of second soft-bias side shields. The magnetic seed layer is pinned such that the magnetic seed layer is magnetized in the same magnetization direction as the upper shield or one or more of the plurality of second soft-bias side shields. The AFM layer is magnetized in the same magnetization direction as the magnetic seed layer. The second reader includes a second AFM layer disposed above the upper shield, and the second AFM layer is magnetized in the same magnetization direction as the AFM layer. A magnetic recording device having a read head is also disclosed.

[0063] In one embodiment, a magnetic device includes a first sensor. The first sensor includes a lower shield, a magnetic seed layer disposed above the lower shield, and a first lower free layer disposed above the magnetic seed layer. The first sensor includes a second lower free layer disposed above the first lower free layer and a second shield disposed above the second lower free layer. The first sensor includes a first antiferromagnetic (AFM) layer disposed above the second shield. The magnetic device includes an insulating separation layer disposed above the first AFM layer and a second sensor. The second sensor includes a magnetic seed layer disposed above the insulating separation layer, a second AFM layer disposed between the magnetic seed layer of a second reader and the insulating separation layer to pin the magnetic seed layer of the second sensor. The second sensor includes a cap layer. The second sensor includes a first upper free layer disposed between the magnetic seed layer and the cap layer of the second sensor, a second upper free layer disposed between the first upper free layer and the cap layer, and an upper shield disposed above the cap layer. The magnetic seed layer of the first sensor includes a platform protruding in a track direction. The upper surface of the platform is disposed at a distance relative to the lower shield. The distance is 100 angstroms or greater. The second sensor also includes a third AFM layer disposed above the upper shield. Each of the first AFM layer, the second AFM layer, and the third AFM layer is magnetized in the same magnetization direction. Also disclosed is a magnetic recording device having the magnetic device.

[0064] In one embodiment, a magnetic device for a magnetic recording device includes a first sensor. The first sensor includes a lower shield, a first lower free layer disposed above the lower shield, and a second lower free layer disposed above the first lower free layer. The first sensor includes a second shield disposed above the second lower free layer. The magnetic device includes an insulating separation layer disposed above the first sensor and a second sensor. The second sensor includes a magnetic seed layer disposed above the insulating separation layer, a first ferromagnetic (FM) layer disposed between the insulating separation layer and the magnetic seed layer, and a second FM layer disposed between the first FM layer and the magnetic seed layer. The first FM layer and the second FM layer are magnetized antiparallel to each other. The second sensor includes a nonmagnetic spacer layer disposed between the first FM layer and the second FM layer. The nonmagnetic spacer layer is formed of ruthenium (Ru). The second sensor includes a cap layer, a first upper free layer disposed between the magnetic seed layer and the cap layer, a second upper free layer disposed between the first upper free layer and the cap layer, and an upper shield disposed above the cap layer. The second sensor includes an antiferromagnetic (AFM) layer disposed between the first FM layer and the insulating separation layer. A magnetic recording device having a magnetic device is also disclosed.

[0065] 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 of the disclosure is to be determined by the claims that follow.

Claims

1. A read head for a magnetic recording device, comprising: A first reader comprising: Lower shield, a first lower free layer disposed above the lower shield, a second lower free layer disposed above the first lower free layer, and a second shielding member, disposed above the second lower free layer; an insulating separation layer disposed above the first reader; and A second reader, the second reader comprising: a magnetic seed layer, disposed above the insulating separation layer, an antiferromagnetic layer disposed between the magnetic seed layer and the insulating separation layer to pin the magnetic seed layer, a non-magnetic spacer layer disposed between the antiferromagnetic layer and the insulating separation layer, cap layer, a first upper free layer, disposed between the magnetic seed layer and the cap layer; a second upper free layer, disposed between the first upper free layer and the cap layer; a barrier layer disposed between the first upper free layer and the second upper free layer, and The upper shielding member is arranged above the cap layer. 2 . The read head of claim 1 , wherein the antiferromagnetic layer has a thickness in a direction along the track, wherein the thickness is in a range of 3 nm to 8 nm.

3. The read head of claim 1, wherein the second reader further comprises a dust layer disposed between the antiferromagnetic layer and the magnetic seed layer, and the dust layer is formed of one or more of ruthenium (Ru) or cobalt iron (CoFe). 4 . The reading head according to claim 3 , wherein a thickness of the dust-proof layer is 1 nm or less. 5 . The read head of claim 1 , wherein the nonmagnetic spacer layer has a thickness of 2 nm or greater. 6 . The read head of claim 1 , wherein the magnetic seed layer comprises a platform protruding in a track direction, an upper surface of the platform is disposed at a distance relative to the antiferromagnetic layer, and the distance is in a range of 10 nm to 30 nm.

7. The readhead of claim 1 , wherein the second reader further comprises: a plurality of first soft-bias side shields disposed above the magnetic seed layer; a second plurality of soft-biased side shields disposed above the first plurality of soft-biased side shields; and A plurality of spacer layers are between the plurality of first soft bias side shields and the plurality of second soft bias side shields.

8. The read head of claim 7, wherein the magnetic seed layer is pinned such that the magnetic seed layer is magnetized in the same magnetization direction as one or more of the plurality of second soft bias side shields or the upper shield.

9. The read head of claim 8, wherein the antiferromagnetic layer is magnetized in the same magnetization direction as the magnetic seed layer.

10. The readhead of claim 9, wherein the second reader further comprises: A second antiferromagnetic layer is above the upper shield, and the second antiferromagnetic layer is magnetized in the same magnetization direction as the antiferromagnetic layer.

11. A magnetic recording device comprising the reading head according to claim 1.

12. A magnetic device comprising: The first sensor comprises: Lower shield, a magnetic seed layer disposed above the lower shield; a first lower free layer disposed above the magnetic seed layer, a second lower free layer, disposed above the first lower free layer; a second shielding member disposed above the second lower free layer; a first antiferromagnetic layer disposed above the second shielding member; an insulating separation layer disposed above the first antiferromagnetic layer; and The second sensor comprises: a magnetic seed layer, disposed above the insulating separation layer, a second antiferromagnetic layer disposed between the magnetic seed layer of the second sensor and the insulating separation layer to pin the magnetic seed layer of the second sensor; cap layer, a first upper free layer disposed between the cap layer and the magnetic seed layer of the second sensor, a second upper free layer, disposed between the first upper free layer and the cap layer; an upper shielding member disposed above the cap layer, and A third antiferromagnetic layer is disposed over the upper shield, wherein each of the first antiferromagnetic layer, the second antiferromagnetic layer, and the third antiferromagnetic layer is magnetized in the same magnetization direction. 13 . The magnetic device of claim 12 , wherein the magnetic seed layer of the first sensor includes a platform protruding in an along-track direction. 14 . The magnetic device of claim 13 , wherein the upper surface of the platform is disposed at a distance relative to the lower shield, and the distance is 100 angstroms or greater.

15. A magnetic recording device comprising the magnetic device according to claim 12.

16. A read head for a magnetic recording device, comprising: A first reader comprising: Lower shield, a first lower free layer disposed above the lower shield, a second lower free layer disposed above the first lower free layer, and a second shielding member, disposed above the second lower free layer; an insulating separation layer disposed above the first reader; and A second reader, the second reader comprising: A magnetic seed layer is provided above the insulating separation layer, wherein the magnetic seed layer includes a platform protruding along the magnetic track direction, a plurality of first soft bias side shields disposed above the magnetic seed layer, a second plurality of soft-biased side shields disposed above the first plurality of soft-biased side shields, a plurality of spacer layers between the plurality of first soft bias side shields and the plurality of second soft bias side shields, an antiferromagnetic layer disposed between the magnetic seed layer and the insulating separation layer to pin the magnetic seed layer, cap layer, a first upper free layer, disposed between the magnetic seed layer and the cap layer; a second upper free layer, disposed between the first upper free layer and the cap layer; a barrier layer disposed between the first upper free layer and the second upper free layer, and An upper shield is disposed over the cap layer, wherein the magnetic seed layer is pinned such that the magnetic seed layer is magnetized in the same magnetization direction as one or more of the plurality of second soft-bias side shields or the upper shield.

17. The read head of claim 16, wherein the antiferromagnetic layer is magnetized in the same magnetization direction as the magnetic seed layer.

18. The readhead of claim 17, wherein the second reader further comprises: A second antiferromagnetic layer is above the upper shield, and the second antiferromagnetic layer is magnetized in the same magnetization direction as the antiferromagnetic layer.

19. A magnetic recording apparatus comprising the read head according to claim 16.

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