Highly sensitive spintronic strain-gauge sensor and Spin-MEMS microphone. (21st May 2019)

• Record Type: Journal Article
• Authors: Fuji, Yoshihiko; Higashi, Yoshihiro; Kaji, Shiori; Masunishi, Kei; Nagata, Tomohiko; Yuzawa, Akiko; Okamoto, Kazuaki; Baba, Shotaro; Ono, Tomio; Hara, Michiko
• Is Part Of: Japanese journal of applied physics. Volume 58:Number SD(2019)
• Publication Date: 2019-05-21
• Subjects: Physics -- Periodicals; 621.05
• DOI: 10.7567/1347-4065/ab12c0
• Languages: English
• ISSNs: 0021-4922

Abstract

Abstract: Strain-gauge sensors consisting of magnetic tunnel junctions (MTJs) have attracted attention because of their high strain sensitivity based on a novel strain sensing scheme different from the piezoresistive effect. To maximize the strain sensitivity of these spintronic strain-gauge sensors (Spin-SGSs), we previously developed an MTJ film with magnetostrictive material that acutely rotates with strain. This review presents a Spin-SGS with a high gauge factor in excess of 5000, which was achieved by adopting an amorphous FeB-based sensing layer with high magnetostriction and low coercivity in a high magnetoresistance Mg–O barrier MTJ. We also investigated the feasibility of using this Spin-SGS in microelectromechanical system (MEMS) sensor devices. This review also describes the properties of a "Spintronic MEMS (Spin-MEMS) microphone, " in which Spin-SGSs are integrated onto a bulk micromachined diaphragm.