Magnetic properties of epitaxial Fe3O4 films with various crystal orientations and tunnel magnetoresistance effect at room temperature

被引：36

作者：

Nagahama, Taro ^{[1
]}

Matsuda, Yuya ^{[1
]}

Tate, Kazuya ^{[1
]}

Kawai, Tomohiro ^{[1
]}

Takahashi, Nozomi ^{[1
]}

Hiratani, Shungo ^{[1
]}

Watanabe, Yusuke ^{[1
]}

Yanase, Takashi ^{[1
]}

Shimada, Toshihiro ^{[1
]}

机构：

[1] Hokkaido Univ, Grad Sch Engn, Kitak Ku, Sapporo, Hokkaido 0608628, Japan

来源：

APPLIED PHYSICS LETTERS | 2014年 / 105卷 / 10期

关键词：

SURFACE-STRUCTURE; JUNCTIONS; ORIGIN;

D O I：

10.1063/1.4894575

中图分类号：

O59 [应用物理学];

学科分类号：

摘要：

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.

引用

页数：4

共 23 条

[1] Spin-polarized conduction in oxide magnetic tunnel junctions with magnetic and nonmagnetic insulating barrier layers [J].