Patents by Inventor James Mac Freitag

James Mac Freitag has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Publication number: 20250246204
    Abstract: The present disclosure generally relates to a two-dimensional magnetic recording (TDMR) read head. The TDMR read head comprises a first sensor, a second sensor, and a middle shield (MS) disposed between the first and second sensors. The MS comprises a seed layer, an IrMn layer disposed on the seed layer, an insertion layer comprising Ru or CoFe disposed on the IrMn layer, a first NiFe layer having a pinned magnetization, and a cap layer disposed over the first NiFe layer. In one embodiment, the MS further comprises an Ru layer disposed on the first NiFe layer and a second NiFe layer disposed on the Ru layer, the second NiFe layer having a pinned magnetization in a direction antiparallel to the first NiFe layer. The insertion layer comprising Ru decreases an exchange energy of the MS. The insertion layer comprising CoFe increases an exchange energy of the MS.
    Type: Application
    Filed: January 29, 2024
    Publication date: July 31, 2025
    Applicant: Western Digital Technologies, Inc.
    Inventors: Yuankai ZHENG, Zhitao DIAO, Chih-Ching HU, Yung-Hung WANG, Chen-Jung CHIEN, Ming MAO, James Mac FREITAG
  • Patent number: 12374356
    Abstract: The present disclosure generally relates to a two-dimensional magnetic recording (TDMR) read head. The TDMR read head comprises a first sensor, a second sensor, and a middle shield (MS) disposed between the first and second sensors. The MS comprises a seed layer, an IrMn layer disposed on the seed layer, an insertion layer comprising Ru or CoFe disposed on the IrMn layer, a first NiFe layer having a pinned magnetization, and a cap layer disposed over the first NiFe layer. In one embodiment, the MS further comprises an Ru layer disposed on the first NiFe layer and a second NiFe layer disposed on the Ru layer, the second NiFe layer having a pinned magnetization in a direction antiparallel to the first NiFe layer. The insertion layer comprising Ru decreases an exchange energy of the MS. The insertion layer comprising CoFe increases an exchange energy of the MS.
    Type: Grant
    Filed: January 29, 2024
    Date of Patent: July 29, 2025
    Assignee: Western Digital Technologies, Inc.
    Inventors: Yuankai Zheng, Zhitao Diao, Chih-Ching Hu, Yung-Hung Wang, Chen-Jung Chien, Ming Mao, James Mac Freitag
  • Publication number: 20250210241
    Abstract: The present disclosure generally relates to topological insulator (TI) based spin-orbit torque (SOT) devices. The SOT device comprises an amorphous seed layer, a textured seed layer having a (001) orientation disposed on the amorphous seed layer, an insulating layer disposed over the textured seed layer, a diffusion barrier layer having a (001) orientation disposed on the insulating layer, a BiSb layer having a (012) orientation disposed on the diffusion barrier layer, an interlayer having a (001) orientation disposed on the BiSb layer, and a ferromagnetic layer having a (001) orientation disposed on the interlayer. The diffusion barrier layer and the interlayer each individually comprises one or more of NiAl and RuAl, and prevent Sb migration from the BiSb layer while transmitting the (001) orientation to the ferromagnetic layer.
    Type: Application
    Filed: December 21, 2023
    Publication date: June 26, 2025
    Applicant: Western Digital Technologies, Inc.
    Inventors: Susumu OKAMURA, Brian R. YORK, James Mac FREITAG
  • Patent number: 12207563
    Abstract: The present disclosure generally relates to magnetoresistive (MR) devices. The MR device comprises a synthetic antiferromagnetic (SAF) layer that increases exchange coupling field, and in turn, less magnetic noise of such devices. The MR device comprises a first ferromagnetic (FM1) layer and a second ferromagnetic (FM2) layer, in between which is an SAF spacer of RuAl alloy having a B2 crystalline structure which may grow epitaxial on BCC (110) or FCC (111) textures, meaning that the (110) or (111) plane is parallel to the surface of MR device substrate. Further, amorphous layers may be inserted into the device structure to reset the growth texture of the device to a (001), (110), or (111) texture in order to promote the growth of tunneling barrier layers or antiferromagnetic (AF) pinning layers.
    Type: Grant
    Filed: September 23, 2022
    Date of Patent: January 21, 2025
    Assignee: Western Digital Technologies, Inc.
    Inventors: Susumu Okamura, James Mac Freitag, Yuankai Zheng, Brian R. York
  • Patent number: 12106784
    Abstract: Embodiments of the present disclosure generally relate to a read sensor utilized in a read head. The read sensor comprises an amorphous break layer disposed on a shield, a seed layer disposed on the amorphous break layer, a first ferromagnetic layer disposed on the seed layer, a barrier layer disposed on the first ferromagnetic layer, and a second ferromagnetic layer disposed on the barrier layer. The amorphous break layer comprises CoFeBTa, the seed layer comprises RuAl, and the barrier layer comprises a semiconductor material, such as ZnSe, ZnTe, ZnO, CuSe, or CuInGaSe. The semiconductor barrier layer reduces the resistance-area product of the read sensor. The amorphous break layer breaks the texture between the shield, which has a FCC texture, and the seed layer, which has a BCC texture. The BCC texture of the seed layer is then inherited by the remaining layers disposed over the seed layer.
    Type: Grant
    Filed: July 28, 2023
    Date of Patent: October 1, 2024
    Assignee: Western Digital Technologies, Inc.
    Inventors: Yuankai Zheng, Susumu Okamura, Brian R. York, Zhitao Diao, James Mac Freitag
  • Patent number: 12094498
    Abstract: The present disclosure generally relates to a spin torque element disposed between a main pole and a shield in a magnetic recording head. The shield could be a trailing shield, a side shield, or a leading shield. The spin torque element includes a dual layer spin transfer structure that is spaced from magnetic layers on either side using spacer layers. One magnetic layer that faces a positive polarizer has a positive polarization while another magnetic layer facing the negative polarizer has a negative polarization. As such, torque in the spacer layers is maximized when the direction of the magnetization in the STL is opposite to the gap field.
    Type: Grant
    Filed: July 19, 2023
    Date of Patent: September 17, 2024
    Assignee: Western Digital Technologies, Inc.
    Inventors: Alexander Goncharov, James Mac Freitag, Susumu Okamura, Muhammad Asif Bashir
  • Patent number: 12040114
    Abstract: The present disclosure generally relates to magnetoresistive (MR) devices. The MR device comprises a synthetic antiferromagnetic (SAF) layer that increases stability to magnetic fields, and in turn, results in lower magnetic noise of the device. The MR device comprises a first ferromagnetic (FM1) layer and a second ferromagnetic (FM2) layer, in between which is an SAF spacer of RuAl alloy having a B2 crystalline structure with (001) texture, meaning that the (001) plane is parallel to the surface of MR device substrate. The first ferromagnetic (FM1) layer and a part of the second ferromagnetic (FM2) layer also have the (001) texture. An amorphous layer in a second ferromagnetic (FM2) layer can reset the growth texture of the MR device to a (111) texture in order to promote the growth of an antiferromagnetic (AF) pinning layer.
    Type: Grant
    Filed: September 14, 2022
    Date of Patent: July 16, 2024
    Assignee: Western Digital Technologies, Inc.
    Inventors: Susumu Okamura, James Mac Freitag, Yuankai Zheng, Brian R. York
  • Publication number: 20240194221
    Abstract: Embodiments of the present disclosure generally relate to a read sensor utilized in a read head. The read sensor comprises an amorphous break layer disposed on a shield, a seed layer disposed on the amorphous break layer, a first ferromagnetic layer disposed on the seed layer, a barrier layer disposed on the first ferromagnetic layer, and a second ferromagnetic layer disposed on the barrier layer. The amorphous break layer comprises CoFeBTa, the seed layer comprises RuAl, and the barrier layer comprises a semiconductor material, such as ZnSe, ZnTe, ZnO, CuSe, or CuInGaSe. The semiconductor barrier layer reduces the resistance-area product of the read sensor. The amorphous break layer breaks the texture between the shield, which has a FCC texture, and the seed layer, which has a BCC texture. The BCC texture of the seed layer is then inherited by the remaining layers disposed over the seed layer.
    Type: Application
    Filed: July 28, 2023
    Publication date: June 13, 2024
    Applicant: Western Digital Technologies, Inc.
    Inventors: Yuankai ZHENG, Susumu OKAMURA, Brian R. YORK, Zhitao DIAO, James Mac FREITAG
  • Publication number: 20240107893
    Abstract: The present disclosure generally relates to magnetoresistive (MR) devices. The MR device comprises a synthetic antiferromagnetic (SAF) layer that increases exchange coupling field, and in turn, less magnetic noise of such devices. The MR device comprises a first ferromagnetic (FM1) layer and a second ferromagnetic (FM2) layer, in between which is an SAF spacer of RuAl alloy having a B2 crystalline structure which may grow epitaxial on BCC (110) or FCC (111) textures, meaning that the (110) or (111) plane is parallel to the surface of MR device substrate. Further, amorphous layers may be inserted into the device structure to reset the growth texture of the device to a (001), (110), or (111) texture in order to promote the growth of tunneling barrier layers or antiferromagnetic (AF) pinning layers.
    Type: Application
    Filed: September 23, 2022
    Publication date: March 28, 2024
    Applicant: Western Digital Technologies, Inc.
    Inventors: Susumu OKAMURA, James Mac FREITAG, Yuankai ZHENG, Brian R. YORK
  • Publication number: 20240087785
    Abstract: The present disclosure generally relates to magnetoresistive (MR) devices. The MR device comprises a synthetic antiferromagnetic (SAF) layer that increases stability to magnetic fields, and in turn, results in lower magnetic noise of the device. The MR device comprises a first ferromagnetic (FM1) layer and a second ferromagnetic (FM2) layer, in between which is an SAF spacer of RuAl alloy having a B2 crystalline structure with (001) texture, meaning that the (001) plane is parallel to the surface of MR device substrate. The first ferromagnetic (FM1) layer and a part of the second ferromagnetic (FM2) layer also have the (001) texture. An amorphous layer in a second ferromagnetic (FM2) layer can reset the growth texture of the MR device to a (111) texture in order to promote the growth of an antiferromagnetic (AF) pinning layer.
    Type: Application
    Filed: September 14, 2022
    Publication date: March 14, 2024
    Applicant: Western Digital Technologies, Inc.
    Inventors: Susumu OKAMURA, James Mac FREITAG, Yuankai ZHENG, Brian R. YORK
  • Patent number: 11925120
    Abstract: Embodiments of the present disclosure generally relate to spintronic devices, and more specifically to self-cooling spintronic devices. In an embodiment, a device is provided. The device includes a spintronic device having a first side and a second side opposite the first side, a first layer disposed on the first side, and a second layer disposed on the second side, the first layer having a Seebeck coefficient that is different from a Seebeck coefficient of the second layer.
    Type: Grant
    Filed: July 28, 2021
    Date of Patent: March 5, 2024
    Assignee: Western Digital Technologies, Inc.
    Inventors: Susumu Okamura, Christian Kaiser, Xinjiang Shen, Yongchul Ahn, James Mac Freitag
  • Patent number: 11881236
    Abstract: The present disclosure generally relates to a magnetic recording head comprising a spintronic device. The spintronic device is disposed between a main pole and a trailing shield of the magnetic recording head. The spintronic device comprises a multilayer spacer layer comprising a Cu layer in contact with a spin torque layer and a spin transparent texture layer disposed on the Cu layer, the spin transparent texture layer comprising AgSn or AgZn. A multilayer notch comprising a CoFe layer is disposed over the spin transparent texture layer of the multilayer spacer layer and a Heusler alloy layer is disposed on the CoFe layer, the Heusler alloy layer comprising CoMnGe, CoFeGe, or CoFeMnGe. The multilayer spacer layer and the multilayer notch result in the spintronic device having a high spin polarization and a reduced critical current.
    Type: Grant
    Filed: June 21, 2022
    Date of Patent: January 23, 2024
    Assignee: Western Digital Technologies, Inc.
    Inventors: James Mac Freitag, Susumu Okamura, Christian Kaiser
  • Patent number: 11862205
    Abstract: The present disclosure generally relates to a magnetic recording device having a magnetic recording head comprising a spintronic device. The spintronic device is disposed between a main pole and a trailing shield at a media facing surface. The spintronic device comprises a spin torque layer (STL) and a multilayer seed layer disposed in contact with the STL. The spintronic device may further comprise a field generation layer disposed between the trailing shield and the STL. The multilayer seed layer comprises an optional high etch rate layer, a heat dissipation layer comprising Ru disposed in contact with the optional high etch rate layer, and a cooling layer comprising Cr disposed in contact with the heat dissipation layer and the main pole. The high etch rate layer comprises Cu and has a high etch rate to improve the shape of the spintronic device during the manufacturing process.
    Type: Grant
    Filed: June 21, 2022
    Date of Patent: January 2, 2024
    Assignee: Western Digital Technologies, Inc.
    Inventors: James Mac Freitag, Yongchul Ahn, Susumu Okamura, Christian Kaiser
  • Publication number: 20230410840
    Abstract: The present disclosure generally relates to a magnetic recording device having a magnetic recording head comprising a spintronic device. The spintronic device is disposed between a main pole and a trailing shield at a media facing surface. The spintronic device comprises a spin torque layer (STL) and a multilayer seed layer disposed in contact with the STL. The spintronic device may further comprise a field generation layer disposed between the trailing shield and the STL. The multilayer seed layer comprises an optional high etch rate layer, a heat dissipation layer comprising Ru disposed in contact with the optional high etch rate layer, and a cooling layer comprising Cr disposed in contact with the heat dissipation layer and the main pole. The high etch rate layer comprises Cu and has a high etch rate to improve the shape of the spintronic device during the manufacturing process.
    Type: Application
    Filed: June 21, 2022
    Publication date: December 21, 2023
    Applicant: Western Digital Technologies, Inc.
    Inventors: James Mac FREITAG, Yongchul AHN, Susumu OKAMURA, Christian KAISER
  • Publication number: 20230410841
    Abstract: The present disclosure generally relates to a magnetic recording head comprising a spintronic device. The spintronic device is disposed between a main pole and a trailing shield of the magnetic recording head. The spintronic device comprises a multilayer spacer layer comprising a Cu layer in contact with a spin torque layer and a spin transparent texture layer disposed on the Cu layer, the spin transparent texture layer comprising AgSn or AgZn. A multilayer notch comprising a CoFe layer is disposed over the spin transparent texture layer of the multilayer spacer layer and a Heusler alloy layer is disposed on the CoFe layer, the Heusler alloy layer comprising CoMnGe, CoFeGe, or CoFeMnGe. The multilayer spacer layer and the multilayer notch result in the spintronic device having a high spin polarization and a reduced critical current.
    Type: Application
    Filed: June 21, 2022
    Publication date: December 21, 2023
    Applicant: Western Digital Technologies, Inc.
    Inventors: James Mac FREITAG, Susumu OKAMURA, Christian KAISER
  • Patent number: 11682420
    Abstract: Certain embodiments are directed to a spin torque oscillator (STO) device in a microwave assisted magnetic recording (MAMR) device. The magnetic recording head includes a seed layer, a spin polarization layer over the seed layer, a spacer layer over the spin polarization layer, and a field generation layer is over the spacer layer. In one embodiment, the seed layer comprises a tantalum alloy layer. In another embodiment, the seed layer comprises a template layer and a damping reduction layer over the template layer. In yet another embodiment, the seed layer comprises a texture reset layer, a template layer on the texture reset layer, and a damping reduction layer on the template layer.
    Type: Grant
    Filed: August 31, 2021
    Date of Patent: June 20, 2023
    Assignee: Western Digital Technologies, Inc.
    Inventors: James Mac Freitag, Zheng Gao, Susumu Okamura, Brian R. York
  • Patent number: 11683993
    Abstract: Aspects of the present disclosure generally relate to a spintronic device for use in a magnetic media drive, a magnetoresistive random access memory device, a magnetic sensor, or a magnetic recording write head. The spintronic device comprises a multilayer structure having a negative anisotropic field and a negative spin polarization. The multilayer structure comprises a plurality of layers, each layer of the plurality of layers comprising a first sublayer comprising Fe and a second sublayer comprising Co. At least one of the first sublayer and the second sublayer comprises one or more of Cr, V, and Ti. The first and second sublayers are alternating. The negative anisotropic field of the multilayer structure is between about ?0.5 T to about ?0.8 T, and an effective magnetization of the multilayer structure is between about 2.4 T to about 2.8 T.
    Type: Grant
    Filed: March 23, 2021
    Date of Patent: June 20, 2023
    Assignee: Western Digital Technologies, Inc.
    Inventors: Susumu Okamura, Christian Kaiser, James Mac Freitag
  • Patent number: 11657836
    Abstract: Aspects of the present disclosure generally relate to a magnetic recording head of a spintronic device, such as a write head of a data storage device, for example a magnetic media drive. In one example, a magnetic recording head includes a main pole, a trailing shield, and a spin torque layer (STL) between the main pole and the trailing shield. The magnetic recording head includes a first layer structure on the main pole, and the first layer structure includes a negative polarization layer. The magnetic recording head also includes a second layer structure disposed on the negative polarization layer and between the negative polarization layer and the STL. The negative polarization layer is an FeCr layer. The second layer structure includes a Cr layer disposed on the FeCr layer, and a Cu layer disposed on the Cr layer and between the Cr layer and the STL.
    Type: Grant
    Filed: January 28, 2022
    Date of Patent: May 23, 2023
    Assignee: Western Digital Technologies, Inc.
    Inventors: James Mac Freitag, Susumu Okamura, Alexander Goncharov, Zheng Gao
  • Patent number: 11646052
    Abstract: A magnetic recording write head and system has a spin-torque oscillator (STO) located between the write head's write pole and trailing shield. The STO's ferromagnetic free layer is located near the write pole with a multilayer seed layer between the write pole and the free layer. The STO's nonmagnetic spacer layer is between the free layer and the STO's ferromagnetic polarizer. The polarizer may be the trailing shield of the write head, one or more separate polarizer layers, or combinations thereof. The STO electrical circuitry causes electron flow from the write pole to the trailing shield. The multilayer seed layer removes the spin polarization of electrons from the write pole, which enables electrons reflected from the polarizer layer to become spin polarized, which creates the spin transfer torque on the magnetization of the free layer. The multilayer seed layer includes a Mn or a Mn-alloy layer.
    Type: Grant
    Filed: April 12, 2021
    Date of Patent: May 9, 2023
    Assignee: Western Digital Technologies, Inc.
    Inventors: James Mac Freitag, Zheng Gao, Masahiko Hashimoto, Sangmun Oh
  • Publication number: 20230030248
    Abstract: Embodiments of the present disclosure generally relate to spintronic devices, and more specifically to self-cooling spintronic devices. In an embodiment, a device is provided. The device includes a spintronic device having a first side and a second side opposite the first side, a first layer disposed on the first side, and a second layer disposed on the second side, the first layer having a Seebeck coefficient that is different from a Seebeck coefficient of the second layer.
    Type: Application
    Filed: July 28, 2021
    Publication date: February 2, 2023
    Inventors: Susumu OKAMURA, Christian KAISER, Xinjiang SHEN, Yongchul AHN, James Mac FREITAG