ヤナセ　タカシ   Yanase Takashi   柳瀨　隆    所属   東邦大学  理学部 化学科    職種   講師
論文種別	原著
言語種別	英語
査読の有無	査読あり
表題	Magnetic properties of epitaxial Fe3O4 films with various crystal orientations and tunnel magnetoresistance effect at room temperature
掲載誌名	正式名：APPLIED PHYSICS LETTERS ISSNコード：0003-6951/1077-3118
出版社	AMER INST PHYSICS
巻・号・頁	105(10)
著者・共著者	Taro Nagahama,Yuya Matsuda,Kazuya Tate,Tomohiro Kawai,Nozomi Takahashi,Shungo Hiratani,Yusuke Watanabe,Takashi Yanase,Toshihiro Shimada
発行年月	2014/09
概要	Fe3O4 is a ferrimagnetic spinel ferrite that exhibits electric conductivity at room temperature (RT). Although the material has been predicted to be a half metal according to ab-initio calculations, magnetic tunnel junctions (MTJs) with Fe3O4 electrodes have demonstrated a small tunnel magnetoresistance (TMR) effect. Not even the sign of the tunnel magnetoresistance ratio has been experimentally established. Here, we report on the magnetic properties of epitaxial Fe3O4 films with various crystal orientations. The films exhibited apparent crystal orientation dependence on hysteresis curves. In particular, Fe3O4(110) films exhibited in-plane uniaxial magnetic anisotropy. With respect to the squareness of hysteresis, Fe3O4 (111) demonstrated the largest squareness. Furthermore, we fabricated MTJs with Fe3O4(110) electrodes and obtained a TMR effect of -12% at RT. The negative TMR ratio corresponded to the negative spin polarization of Fe3O4 predicted from band calculations. (C) 2014 AIP Publishing LLC.
DOI	10.1063/1.4894575
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