Invention Grant
- Patent Title: Device of evaluating magnetic read head and method of evaluating magnetic read head
- Patent Title (中): 磁读头评估装置及磁读头评估方法
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Application No.: US12385054Application Date: 2009-03-30
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Publication No.: US07990137B2Publication Date: 2011-08-02
- Inventor: Yosuke Antoku
- Applicant: Yosuke Antoku
- Applicant Address: JP Tokyo
- Assignee: TDK Corporation
- Current Assignee: TDK Corporation
- Current Assignee Address: JP Tokyo
- Agency: Oliff & Berridge, PLC
- Main IPC: G01R33/12
- IPC: G01R33/12
Abstract:
An MR element having a magnetically free layer and a magnetic bias layer that applies a bias magnetic field to the magnetically free layer are included. Furthermore, a measuring section that measures a ferromagnetic resonance frequency f0 of the magnetically free layer under a condition of applying a predetermined external magnetic field Hm to the magnetically free layer, and an operation section that computes the bias magnetic field Hb according to a following conditional expression (1): Hb={(2*π*f0/γ)2/Ms}−(Hk+Hm) (1) where γ is a gyroscope constant, Ms is a saturation magnetic field of the magnetically free layer, and Hk is a shape anisotropy magnetic field of the magnetically free layer.
Public/Granted literature
- US20100246042A1 Device of evaluating magnetic read head and method of evaluating magnetic read head Public/Granted day:2010-09-30
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