James Mac Freitag

This inventor holds 110 USPTO granted patents and 14 published patent applications and 2 EPO patents, primarily in Spintronic Devices (CPC class G11B5-314). Top assignees: Hitachi Global Storage Technologies Netherlands B.v., Western Digital Technologies, Inc., Hgst Netherlands, B.v.. Active years: 2003-2026.

USPTO Granted Patents = 110 (Patent Applications = 14)

% Patents Active = 47.3

EPO Patents = 2 (Patent Applications = 3)

Average Co-Inventor Count = 3.0

ph-index = 14

Forward Citations = 633(Granted Patents)

Forward Citations (Not Self Cited) = 546(Dec 10, 2025)

Inventors with similar research interests:

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Location History:

San Jose, CA (US) (2003 - 2012)
Sunnyvale, CA (US) (2008 - 2024)

Company Filing History:

49 out of 2,636

Hitachi Global Storage Technologies Netherlands B.v.

patents

41 out of 5,422

Western Digital Technologies, Inc.

patents

10 out of 987

Hgst Netherlands, B.v.

patents

4. 5 out of 166,209

International Business Machines Corporation

patents

5. 2 out of 52

Hitachi Global Storage Technologies

Solopower Systems, Inc.

patents

Years Active: 2003-2026

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Areas of Expertise:

Spin Torque Oscillator

Magnetoresistive Sensor

Magnetic Recording

Synthetic Antiferromagnet

Heusler Alloy

Magnetic Tunnel Junction

Spin Transfer Torque

Magnetostriction Control

Microwave Assisted Recording

Negative Spin Polarization

High Moment Free Layers

Self-Cooling Function

110 patents (USPTO):Sort by Forward CitationsExplore Patents

1. 12731604 - Shield designs for two dimensional magnetic recording read heads (2026-09-08),

2. 12688867 - Read sensor with a layer having an adjustable etching rate (2026-07-21),

3. 12374356 - Pinned shield with controllable exchange bias field (2025-07-29),

4. 12207563 - Magnetoresistive devices comprising a synthetic antiferromagnetic coupling layer of RuAl having a (110) texture (2025-01-21),

5. 12106784 - Read sensor with ordered heusler alloy free layer and semiconductor barrier layer (2024-10-01),

6. 12094498 - Recording head with a multilayer spin torque element having positive and negative beta materials (2024-09-17),

7. 12040114 - Magnetoresistive device comprising a synthetic antiferromagnetic coupling layer of RuAl having a (001) texture (2024-07-16),

8. 11925120 - Spintronic devices with self-cooling function (2024-03-05),

9. 11881236 - Spin torque oscillator with enhanced spin polarizer (2024-01-23),

10. 11862205 - Spin torque oscillator with multilayer seed for improved performance and reliability (2024-01-02),

11. 11683993 - Material having both negative spin polarization and negative anisotropy (2023-06-20),

12. 11682420 - Seed layer for spin torque oscillator in microwave assisted magnetic recording device (2023-06-20),

13. 11657836 - Magnetic recording devices having negative polarization layer to enhance spin-transfer torque (2023-05-23),

14. 11646052 - Spin-torque oscillator with multilayer seed layer between the write pole and the free layer in a magnetic recording write head (2023-05-09),

15. 11289118 - Spintronic device having negative interface spin scattering (2022-03-29),

James Mac Freitag is an American inventor based in Sunnyvale, CA, who has made remarkable contributions in the field of spintronics devices and magnetic recording devices. He has over 100 patents to his name and is highly regarded in the industry for his innovative ideas.

His latest patents are a material having both negative spin polarization and negative anisotropy and a seed layer for a spin torque oscillator in a microwave assisted magnetic recording device. The negative anisotropy field and negative spin polarization of the multilayer structure make it ideal for use in magnetic media drives, magnetoresistive random access memory devices, magnetic sensors, and magnetic recording write heads. The seed layer he invented is used in spin torque oscillator devices of microwave assisted magnetic recording devices and can include a tantalum alloy layer, template layer, damping reduction layer, texture reset layer, and more.

Freitag has a vast experience in the technology industry, having worked for big corporations like Western Digital Technologies, Inc., and HGST Netherlands B.V. His coworkers Mustafa Pinarbasi and Zheng Gao, note that he is not only an accomplished inventor but also an excellent team player and collaborator.

Freitag's contribution to spintronics devices, magnetic recording devices, and other related fields has placed him among the top inventors in the industry. His insightful patents continue to impact and shape various technology industries globally.