Origin of ferromagnetism in ZnO codoped with Ga and Co: Experiment and theory

被引：72

作者：

He, Y. ^{[1
,2
]}

Sharma, Parmanand ^{[3
]}

Biswas, Krishanu ^{[4
]}

Liu, E. Z. ^{[1
,2
]}

Ohtsu, Naofumi ^{[3
]}

Inoue, A. ^{[3
]}

Inada, Y. ^{[5
]}

Nomura, M. ^{[5
]}

Tse, J. S. ^{[1
,2
,6
]}

Yin, S. ^{[1
,2
]}

Jiang, J. Z. ^{[1
,2
]}

机构：

[1] Zhejiang Univ, ICNSM, Hangzhou 310027, Peoples R China

[2] Zhejiang Univ, Dept Mat Sci & Engn, Lab New Struct Mat, Hangzhou 310027, Peoples R China

[3] Tohoku Univ, Inst Mat Res, Aoba Ku, Sendai, Miyagi 9808577, Japan

[4] Indian Inst Technol, Dept Mat & Met Engn, Kanpur 208016, Uttar Pradesh, India

[5] High Energy Accelerator Res Org, Inst Mat Struct Sci, Tsukuba, Ibaraki 3050801, Japan

[6] Univ Saskatchewan, Dept Phys & Engn Phys, Saskatoon, SK S7N 5E2, Canada

来源：

PHYSICAL REVIEW B | 2008年 / 78卷 / 15期

基金：

中国国家自然科学基金;

关键词：

D O I：

10.1103/PhysRevB.78.155202

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

In view of the recent controversies on the above room-temperature ferromagnetism in pure ZnO and the transition-metal doped ZnO, the present paper aims to shed some light on the origin of ferromagnetism by investigating the detailed atomic structure of (Co, Ga)-codoped ZnO experimentally as well as theoretically. Above room-temperature ferromagnetism in nonmagnetic Co-doped ZnO, nanoparticle powders prepared by sol-gel technique were obtained by codoping with Ga. It is found that Co ions substitute Zn sites while Ga ions were located at octahedral interstitial sites together with one O vacancy. Electrons from the Ga 4p(up arrow) states transform to the unfilled Co 3d(down arrow) states. The strong hybridization between the charge carriers in the Co 3d and Ga 4p states and electronic polarization for surrounding O ions at Co ions are detected. Finally, the Ga-4p electrons merged with conduction band and polarized O ions act as medium for an indirect exchange between the Co ions, which could be the origin of ferromagnetism in the (Co, Ga)-codoped ZnO.

引用

页数：7

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