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)

11:30 〜 11:45

[19a-331-10] Tunnel Magnetocapacitance in Single-layered Fe/MgF2 Granular Films

Robin Msiska1、Shusaku Honjo2、Yuki Asai2、Masashi Arita2、Atsushi Tsurumaki-Fukuchi2、Yasuo Takahashi2、Norihisa Hoshino3、Tomoyuki Akutagawa3、Osamu Kitakami3、Masaya Fujioka1、Junji Nishii1、Hideo Kaiju1 (1.RIES, Hokkaido Univ.、2.IST, Hokkaido Univ.、3.IMRAM, Tohoku Univ.)

キーワード:Magnetocapacitance, Granular Films, Nanostructures

Magnetocapacitance (MC) effects lead to some appealing spin-based phenomena such as frequency-dependent spin transport and spin capacitance, which are crucial for spintronic devices. MC offers attractive prospects for materials research and device applications such as high-frequency devices and energy storage. Here we report tunnel magnetocapacitance (TMC) in single-layered Fe/MgF2 granular films. As a result, at 40 Hz, the TMC ratio with 1 kOe reaches 1.45%, which is larger than the value (0.8%) previously reported in two-dimensional (2D) Co/AlF granular films. The TMC ratio reaches up to 2.89% at 30 Hz, which is the highest value ever reported for 2D granular films. A combination of the Debye-Fröhlich (DF) model and the Julliere formula was used to fit the experimental data to theory, and an excellent agreement between the calculated values and the experimental data was obtained. To perfectly fit the data, the conventional DF model was extended to a three-phase model in which three capacitors were introduced. Our findings will give further insight into the exact mechanism of TMC effect in nanogranular films, and will open broader opportunities for device applications, such as magnetic sensors and impedance tunable devices.