Significant magnetoresistance enhancement due to a cotunneling process in a double tunnel junction with single discontinuous ferromagnetic layer insertion

被引：42

作者：

Sukegawa, H ^{[1
]}

Nakamura, S

Hirohata, A

Tezuka, N

Inomata, K

机构：

[1] Tohoku Univ, Grad Sch Engn, Dept Mat Sci, Aoba Ku, Sendai, Miyagi 9808579, Japan

[2] Toshiba Nanoanal Corp, Isogo Ku, Yokohama, Kanagawa 2358522, Japan

[3] Japan Sci & Technol Agcy, CREST, Kawaguchi 3320012, Japan

来源：

PHYSICAL REVIEW LETTERS | 2005年 / 94卷 / 06期

关键词：

D O I：

10.1103/PhysRevLett.94.068304

中图分类号：

O4 [物理学];

学科分类号：

0702 ;

摘要：

We fabricate CoFe/AlOx/CoFe/AlOx/CoFe ferromagnetic double tunnel junctions and observe spindependent tunneling phenomena. A middle CoFe layer becomes discontinuous by forming CoFe particles two dimensionally, of which the average diameter is evaluated to be 2.0-4.5 nm from cross-sectional transmission electron microscopy images. Below 50 K, a Coulomb gap is observed in current-voltage curves, and both magnetoresistance ratios and resistances are found to increase significantly with decreasing temperature. This indicates that a cotunneling process is dominant within the gap, which agrees very well with theoretical prediction [Phys. Rev. Lett. 80, 1758 (1998)].

引用

页数：4

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