Tunnel magnetoresistance in epitaxial magnetic tunnel junctions using full-Heusler alloy Co2MnGe thin film and MgO tunnel barrier

被引：27

作者：

Marukame, T ^{[1
]}

Ishikawa, T ^{[1
]}

Matsuda, K ^{[1
]}

Uemura, T ^{[1
]}

Yamamoto, M ^{[1
]}

机构：

[1] Hokkaido Univ, Grad Sch Informat Sci & Technol, Div Elect Informat, Kita Ku, Sapporo, Hokkaido 0600814, Japan

来源：

JOURNAL OF APPLIED PHYSICS | 2006年 / 99卷 / 08期

关键词：

Electrochemical electrodes - Electron tunneling - Epitaxial growth - Magnesium compounds - Magnetoresistance - Thin films;

D O I：

10.1063/1.2167063

中图分类号：

O59 [应用物理学];

学科分类号：

摘要：

We fabricated fully epitaxial magnetic tunnel junctions (MTJs) using a Co-based full-Heusler alloy Co2MnGe (CMG) thin film as a lower electrode, an MgO tunnel barrier, and a Co50Fe50 upper electrode and investigated their tunnel magnetoresistance (TMR) characteristics. The microfabricated MTJs showed strongly temperature-dependent TMR characteristics with typical TMR ratios of 70% at 7 K and 14% at room temperature (RT). Furthermore, the TMR characteristics exhibited the following notable features in the bias voltage (V) dependence: (1) a cusplike V dependence within a range of similar to +/- 200 mV around V=0 at 7 K, which was smeared out at RT, and (2) a V dependence with pronounced asymmetry regarding the polarity, showing negative TMR ratios in a certain negative bias voltage range around -400 mV at both 7 K and RT (V was defined with respect to the lower CMG electrode). A possible transport mechanism leading to the notably asymmetric V dependence along with the negative TMR for a certain bias voltage region is direct tunneling that reflects the spin-dependent density of states of the CMG electrode. (C) 2006 American Institute of Physics.

引用

页数：3

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