Patents Assigned to Headway Technologies, Inc.
  • Patent number: 10991386
    Abstract: A junction shield (JS) structure is disclosed for providing longitudinal bias to a free layer (FL) having a width (FLW) and magnetization in a cross-track direction between sidewalls in a sensor. The sensor is formed between bottom and top shields and has sidewalls extending from a front side at an air bearing surface (ABS) to a backside that is a stripe height (SH) from the ABS. The JS structure has a single layer (JS1) adjacent to each sensor sidewall and with a magnetization parallel to that of the FL, and a tapered top surface such that JS1 has decreasing thickness with increasing height from the ABS. As aspect ratio or AR (SH/FLW) increases above 1, longitudinal bias increases proportionally to slow an increase in asymmetry as AR increases, and without introducing a loss in amplitude for a reader with low AR.
    Type: Grant
    Filed: June 23, 2020
    Date of Patent: April 27, 2021
    Assignee: Headway Technologies, Inc.
    Inventors: Urmimala Roy, Yan Wu
  • Patent number: 10991391
    Abstract: A preamplifier has a pre-compensation circuit that optimizes the write current in a low current range of less than 30 mA. The pre-compensation circuit maintains the peak current with a high overshoot current amplitude for achieving an optimized areal density capability to equalize the erase widths for the bit lengths of the encoded data with bit lengths greater than three clock time periods with encoded data with a bit length of the two clock time period. Alternately, the pre-compensation circuit has an overshoot generator that determines the optimum amplitude of the overshoot current for the bit-lengths for the encoded data. An overshoot data synchronizer is connected to a read current preamplifier to receive a pseudorandom read data signal that is applied to the overshoot generator to enable the different overshoot current amplitude depending on the bit length of the encoded data. The pre-compensated data current is transferred to the write head.
    Type: Grant
    Filed: February 4, 2020
    Date of Patent: April 27, 2021
    Assignee: Headway Technologies, Inc.
    Inventors: Yuhui Tang, Ying Liu, Takeo Kagami, Mei Ki Yeung, Sui Yan Chan
  • Patent number: 10984824
    Abstract: A junction shield (JS) structure and method of forming the same are disclosed for providing longitudinal bias to a free layer (FL) having a width (FLW) and magnetization in a cross-track direction between sidewalls in a sensor. The sensor is formed between bottom and top shields and has sidewalls extending from a front side at an air bearing surface (ABS) to a backside at a stripe height (SH) from the ABS. The JS structure has a lower layer (JS1) with magnetization parallel to that of the FL, and a tapered top surface such that JS1 has decreasing thickness with increasing height from the ABS. As aspect ratio or AR (SH/FLW) increases above 1, longitudinal bias increases proportionally to slow an increase in asymmetry as AR increases, and without decreasing amplitude for a reader with low AR. The JS1 layer may be antiferromagnetically coupled to an upper JS layer for stabilization.
    Type: Grant
    Filed: June 30, 2020
    Date of Patent: April 20, 2021
    Assignee: Headway Technologies, Inc.
    Inventors: Urmimala Roy, Yan Wu
  • Patent number: 10950261
    Abstract: The use of supermalloy-like materials such as NiFeMe where Me is one or more of Mo, Cr, and Cu for the side and top shields of a magnetic bit sensor is shown to provide better shielding protection from stray fields because of their extremely high permeability. Moreover, the side shield may comprise a stack in which a Ni, Fe, Co, FeNi, CoFe, or FeCo is sandwiched between two NiFeMe layers to enhance the bias field on an adjacent free layer. Including NiFeMe in a side shield results in an increase in readback amplitude under the same asymmetric sigma. For these sensors, the signal to noise ratio was higher and the bit error rate was lower than with conventional materials in the side shield. A method is disclosed for forming a magnetic bit sensor having supermalloy-like materials in the side shields.
    Type: Grant
    Filed: August 28, 2018
    Date of Patent: March 16, 2021
    Assignee: Headway Technologies, Inc.
    Inventors: Yewhee Chye, Kunliang Zhang, Min Li
  • Patent number: 10950262
    Abstract: An MTJ or MR read sensor is formed by depositing a stack in a reverse order with a free layer (FL) deposited on a lower shield, followed by a tunneling barrier layer (for an MTJ) or a conducting spacer layer (for an MR) and, finally, an antiferromagnetically coupled pinning structure and an upper shield. This reverse order permits a series of etching processes to be accurately performed on the lower shield and the stack together with the formation of biasing layers that are coupled to the lower shield and the stack, without adversely affecting the stability of the pinning structure. Further, the distance between the FL and the shield is accurately determined and repeatable even down to the sub-nm regime. An upper shield can then be formed and also coupled to the biasing layers.
    Type: Grant
    Filed: June 8, 2020
    Date of Patent: March 16, 2021
    Assignee: Headway Technologies, Inc.
    Inventors: Wenyu Chen, Yan Wu
  • Patent number: 10950257
    Abstract: A method of forming a spin torque assisted magnetic recording writer is disclosed wherein a spin flipping (STO) device is recessed from an air bearing surface. The STO device has a middle flux guiding layer with a magnetization that flips to a direction anti-parallel to the write gap field when a current of sufficient magnitude is applied from the trailing shield towards the main pole (MP) thereby increasing reluctance in the write gap to enhance writability. A STO stack is deposited and patterned to define a cross-track width on the MP tapered trailing side. Thereafter, the STO stack is patterned to define a STO device with a front side recessed from the air bearing surface, and a backside. A write gap is deposited surrounding the STO device, and has a thickness greater than or ? to STO thickness to enable design flexibility. Then, first and second trailing shields are formed.
    Type: Grant
    Filed: November 14, 2018
    Date of Patent: March 16, 2021
    Assignee: Headway Technologies, Inc.
    Inventors: Yuhui Tang, Ying Liu, Min Li
  • Patent number: 10950782
    Abstract: A magnetic tunnel junction (MTJ) is disclosed wherein a nitride diffusion barrier (NDB) has a L2/L1/NL or NL/L1/L2 configuration wherein NL is a metal nitride or metal oxynitride layer, L2 blocks oxygen diffusion from an adjoining Hk enhancing layer, and L1 prevents nitrogen diffusion from NL to the free layer (FL) thereby enhancing magnetoresistive ratio and FL thermal stability, and minimizing resistance x area product for the MTJ. NL is the uppermost layer in a bottom spin valve configuration, or is formed on a seed layer in a top spin valve configuration such that L2 and L1 are always between NL and the FL or pinned layer, respectively. In other embodiments, one or both of L1 and L2 are partially oxidized. Moreover, either L2 or L1 may be omitted when the other of L1 and L2 is partially oxidized. A spacer between the FL and L2 is optional.
    Type: Grant
    Filed: February 14, 2019
    Date of Patent: March 16, 2021
    Assignee: Headway Technologies, Inc.
    Inventors: Santiago Serrano Guisan, Luc Thomas, Jodi Mari Iwata, Guenole Jan, Vignesh Sundar
  • Patent number: 10943613
    Abstract: A thermally assisted magnetic head including a slider and a light source-unit. The slider includes a slider substrate and a magnetic head part. The light source-unit includes a laser diode and a sub-mount. The magnetic head part includes a medium-opposing surface, a light source-opposing surface and a waveguide which guides laser light from the light source-opposing surface to the medium-opposing surface. The slider substrate includes a light source-cavity formed in a light source-placing surface on which the light source-unit is placed. The light source-cavity includes an opening concave part being formed larger than a mount bottom surface of the sub-mount. The mount bottom surface of the sub-mount is inserted into the opening concave part to be joined to the light source-cavity.
    Type: Grant
    Filed: March 13, 2020
    Date of Patent: March 9, 2021
    Assignees: SAE Magnetics (H.K.) Ltd., Headway Technologies, Inc.
    Inventors: Ryo Hosoi, Takashi Honda, Seiichi Takayama, Sik Fun Chan, Tai Boon Lee, Dayu Zhou
  • Patent number: 10937450
    Abstract: A spin transfer torque reversal assisted magnetic recording (STRAMR) device is disclosed wherein a flux guiding layer (FGL) magnetization flips to an opposite direction opposing the write gap (WG) field because of spin torque from an adjacent spin polarization (SP) layer and spin injection layer (SIL) when a current (Ia) of sufficient density is applied across the device and between the main pole (MP) and trailing shield (TS) thereby enhancing the MP write field. The SP layer adjoins the MP or TS and maintains a magnetization in the WG field direction. One or both of the SIL and FGL has a spin polarization from ?0.4 to 0.3 and may be doped with C, N, or B so that the extent of FGL flipping is greater at a given current density than in the prior art where all magnetic layers within the STRAMR device have a positive spin polarization ?0.4.
    Type: Grant
    Filed: July 13, 2020
    Date of Patent: March 2, 2021
    Assignee: Headway Technologies, Inc.
    Inventors: Shohei Kawasaki, Wenyu Chen, Tetsuya Roppongi
  • Patent number: 10916263
    Abstract: A write head configured for thermally assisted magnetic recording (TAMR) has a split-yoke design that allows the yoke and magnetic pole to be formed as planar layers while the split between left and right-side portions of the yoke and magnetic pole eliminate adverse coupling between the magnetic writing field and the optical near-field heating field. The planar design is easy to fabricate and provides rapid rise time and a strong magnetic field using fewer current-carrying coils than in the prior art.
    Type: Grant
    Filed: November 5, 2019
    Date of Patent: February 9, 2021
    Assignee: Headway Technologies, Inc.
    Inventors: Alain Truong, Tobias Maletzky
  • Patent number: 10916261
    Abstract: A PMR writer with a true one turn design is disclosed with a driving coil above the main pole (MP) but where a bucking coil below the MP is replaced by a dummy metal layer or fully removed to substantially enhance the return field to the trailing shield. A non-double write shield scheme is employed where the leading loop for magnetic flux return is terminated at the leading shield. A tapered bottom yoke (tBY) contacts the MP bottom surface and has a tapered front side at height tBYd from the air bearing surface. Bottom yoke (BY) is below the tBY and has a front side at height BYd where BYd>tBYd. Reader-writer separation is reduced by 1-2 microns when the bucking coil is fully removed. Wide adjacent track erasures are controlled with a high damping material in one or more of the leading, side and trailing shields.
    Type: Grant
    Filed: November 4, 2019
    Date of Patent: February 9, 2021
    Assignee: Headway Technologies, Inc.
    Inventor: Yue Liu
  • Patent number: 10872628
    Abstract: A near field transducer (NFT) is formed between a waveguide and main pole at an air bearing surface (ABS). The NFT includes a rod-like front portion (PG1) and a substantially triangular shaped back portion (PG2) with a dielectric separation layer therebetween. PG1 is formed on a first dielectric layer with thickness t1 and refractive index (RI1) while PG2 is on a second dielectric layer with thickness t2 and having refractive index (RI2) where t1>t2, and RI1>RI2 while PG1 has a tapered backside at angle 45+15 degrees to promote efficient energy transfer from PG2 to PG1 and reduce NFT heating. A dielectric layer that induces poor adhesion with PG1 may be inserted between below PG1 at the ABS to cause Au recession to occur at the PG1 leading side thereby preventing voids at the PG1 trailing side and ensuring good ADC performance.
    Type: Grant
    Filed: February 25, 2020
    Date of Patent: December 22, 2020
    Assignee: Headway Technologies, Inc.
    Inventors: Koji Shimazawa, Weihao Xu
  • Patent number: 10872623
    Abstract: A spin transfer torque reversal assisted magnetic recording (STRAMR) device is disclosed wherein a flux change layer (FCL) is formed between a main pole (MP) trailing side and a trailing shield (TS). The FCL has a magnetization that flips to a direction substantially opposing the write gap magnetic field when a direct current (DC) of sufficient current density is applied across the STRAMR device thereby increasing reluctance in the WG and producing a larger write field output at the air bearing surface. Heat transfer in the STRAMR device is enhanced and production cost is reduced by enlarging the STRAMR width to be essentially equal to that of the TS, and where the TS and STRAMR widths are formed using the same process steps. Bias voltage is used to control the extent of FCL flipping to a center portion to optimize the gain in area density capability in the recording system.
    Type: Grant
    Filed: February 4, 2020
    Date of Patent: December 22, 2020
    Assignee: Headway Technologies, Inc.
    Inventor: Yan Wu
  • Patent number: 10872624
    Abstract: A magnetic head includes a coil, a main pole, a write shield, a lower return path section, and an accommodation section. The accommodation section accommodates at least part of the return path section. A first portion of the accommodation section has a first inclined surface. A second portion of the accommodation section has a second inclined surface. A coil element of the coil has a third inclined surface opposed to the first inclined surface, and a fourth inclined surface opposed to the second inclined surface. The lower return path section includes a first inclined portion extending along the first inclined surface, and a second inclined portion extending along the second inclined surface.
    Type: Grant
    Filed: October 17, 2019
    Date of Patent: December 22, 2020
    Assignee: HEADWAY TECHNOLOGIES, INC.
    Inventors: Yoshitaka Sasaki, Hiroyuki Ito, Kazuki Sato, Shigeki Tanemura, Hironori Araki, Yukinori Ikegawa
  • Patent number: 10861486
    Abstract: A PMR (perpendicular magnetic recording) write head configured for microwave assisted magnetic recording (MAMR) includes a spin-torque oscillator (STO) and trailing shield formed of high moment magnetic material (HMTS). By patterning the STO and the HMTS in a simultaneous process the HMTS and the STO layer are precisely aligned and have very similar cross-track widths. In addition, the write gap at an off-center location has a thickness that is independent from its center-track thickness and the write gap total width can have a flexible range whose minimum value is the same width as the STO width.
    Type: Grant
    Filed: July 10, 2019
    Date of Patent: December 8, 2020
    Assignee: Headway Technologies, Inc.
    Inventors: Yuhui Tang, Ying Liu
  • Patent number: 10839829
    Abstract: A magnetic head includes a medium facing surface, a coil, a main pole, and a substrate. The main pole includes a first layer, and a second layer lying on the first layer. The first layer includes a thickness-changing portion whose dimension in a direction perpendicular to a top surface of the substrate decreases with decreasing distance to the medium facing surface. At least part of the second layer is located on the thickness-changing portion.
    Type: Grant
    Filed: September 27, 2019
    Date of Patent: November 17, 2020
    Assignee: HEADWAY TECHNOLOGIES, INC.
    Inventors: Yoshitaka Sasaki, Hiroyuki Ito, Kazuki Sato, Shigeki Tanemura, Tetsuya Roppongi, Kei Hirata, Atsushi Yamaguchi, Michitaka Nishiyama
  • Patent number: 10839843
    Abstract: A method of operating an HDD having a slider-mounted read/write head that is configured for dynamic fly-height operation (DFH) and includes at least one head-disk interference sensor (HDIs). By operating the DFH to lower the head and subjecting the HDIs signal to a power-law enhancement, a consistent and accurate determination of the touchdown power (TDP) can be obtained. Combining absolute TDP determination with a method for measuring relative changes of FH, an absolute determination of FH can be determined.
    Type: Grant
    Filed: August 30, 2019
    Date of Patent: November 17, 2020
    Assignees: SAE Magnetics (H.K.) Ltd., Headway Technologies, Inc.
    Inventors: Qinghua Zeng, Soramany Ka, Ellis Cha
  • Patent number: 10832707
    Abstract: A perpendicular magnetic recording writer has a main pole (MP) with a first flux guiding (FG) device in a write gap between the MP trailing side and a trailing shield, and a second FG device in the leading gap (LG) and each side gap (SG). The SG angle is reduced to 15° to 45° to enable conformal and more uniform FG device layers to be formed in the SG and LG. As a result, the MP shape and write field are more reproducible. To compensate for a thinner MP thickness at the air bearing surface that results from maintaining the track width at a shallower SG angle, an upper MP tip may be formed on the lower MP tip thereby generating a hexagonal shape for the combined MP tip. In this case, the second FG device conforms to the shape of the two upper MP tip sides and trailing side.
    Type: Grant
    Filed: June 30, 2020
    Date of Patent: November 10, 2020
    Assignee: Headway Technologies, Inc.
    Inventors: Wenyu Chen, Ying Liu, Yan Wu, Yuhui Tang
  • Patent number: 10811034
    Abstract: A microwave-assisted magnetic recording writer is disclosed wherein a heat sink is formed in a write gap (WG) and adjacent to a spin torque oscillator (STO) formed between a main pole (MP) trailing side and a trailing shield (hot seed layer). The WG comprises an electrically insulating layer with thickness of 5-80 Angstroms on the MP trailing side and STO sides. The heat sink layer may be separate coplanar layers on each STO side, or a single layer wrapping around the STO. A Ru or Cu heat sink has sufficient thermal conductivity to reduce STO temperature rise by 11% and 20%, respectively. Accordingly, the STO has longer lifetime at the same bias current density, or higher buffer head voltage is possible while maintaining STO device reliability. Each heat sink has a front side at an air bearing surface, and a stripe height (SH)?to the STO SH.
    Type: Grant
    Filed: April 1, 2019
    Date of Patent: October 20, 2020
    Assignee: Headway Technologies, Inc.
    Inventors: Yan Wu, Kowang Liu
  • Patent number: 10811046
    Abstract: A slider design for a hard disk drive (HDD) features a shallow cavity adjacent to a leading edge that has patterns of sub-cavities of various shapes etched into its base to reduce its original surface area. The presence of these patterns of sub-cavities significantly reduces the probability that the slider will capture particles on the surface of a rotating disk and thereby reduces the corresponding probability of surface scratches that such captured particles inevitably produce.
    Type: Grant
    Filed: July 12, 2018
    Date of Patent: October 20, 2020
    Assignees: SAE Magnetics (H.K.) Ltd., Headway Technologies, Inc.
    Inventors: Ben Ng Kwun Pan, Ellis Cha