Invention Grant
- Patent Title: Adaptive bias control for magnetic recording head
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Application No.: US17856585Application Date: 2022-07-01
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Publication No.: US11887635B2Publication Date: 2024-01-30
- Inventor: Glen Garfunkel , Yan Wu , Wenyu Chen , Kunliang Zhang , Min Li , Shohei Kawasaki
- Applicant: Headway Technologies, Inc.
- Applicant Address: US CA Milpitas
- Assignee: Headway Technologies, Inc.
- Current Assignee: Headway Technologies, Inc.
- Current Assignee Address: US CA Milpitas
- Agency: Saile Ackerman LLC
- Agent Stephen B. Ackerman
- The original application number of the division: US17081235 2020.10.27
- Main IPC: G11B5/39
- IPC: G11B5/39 ; G11B5/00 ; G11B5/48

Abstract:
A read head includes a permanent magnet (PM) layer formed up to 100 nm behind a free layer where PM layer magnetization may be initialized in a direction that adjusts free layer (FL) bias point, and shifts sensor asymmetry (Asym) closer to 0% for individual heads at slider or Head Gimbal Assembly level to provide a significant improvement in device yield. Asym is adjusted using different initialization schemes and initialization directions. With individual heads, initialization direction is selected based on a prior measurement of asymmetry. The PM layer is CoPt or CoCrPt and has coercivity from 500 Oersted to 1000 Oersted. The PM layer may have a width equal to the FL, or in another embodiment, the PM layer adjoins a backside of the top shield and has a width equal to or greater than that of the FL.
Public/Granted literature
- US20220335969A1 Adaptive Bias Control for Magnetic Recording Head Public/Granted day:2022-10-20
Information query
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