2018年第79回応用物理学会秋季学術講演会

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10 スピントロニクス・マグネティクス » 10.3 スピンデバイス・磁気メモリ・ストレージ技術

[19a-331-7~12] 10.3 スピンデバイス・磁気メモリ・ストレージ技術

2018年9月19日(水) 10:45 〜 12:15 331 (国際会議室)

鈴木 和也(東北大)

11:15 〜 11:30

[19a-331-9] Sensitivity improvement of a strain direction sensor using an exchange bias

Hiroki Matsumoto1、Shinya Ota1、Akira Ando2、Tomohiro Koyama1、Daichi Chiba1 (1.Univ. of Tokyo、2.Murata Manufacturing Co., Ltd.)

キーワード:GMR, strain sensor, exchange bias

A magnetization of a ferromagnetic thin film deposited on a flexible substrate can be controlled by an application of tensile strain . Based on this, we have recently demonstrated a strain direction sensing using a Co/Cu/Py giant magnetoresistive (GMR) device formed on a flexible substrate . In this structure, the relative angle of magnetizations between the strain-sensitive Co free layer and strain-insensitive Py pinned layer depends on the strain direction, which can be detected from the modulation of device resistance R through the GMR effect. More than 1% of strain, however, has been needed to detect accurately the strain direction because of a necessity of an auxiliary field Ha for retaining the strain-insensitive Py layer a single domain state. Ha even disturbs the strain-induced free rotation of the strain-sensitive Co magnetization, and thus, has caused the low sensitivity. In this work, we develop a strain direction sensor that enables an Ha-free operation by use of an exchange bias (EB) which is effective only to the Py layer.