Enhancement of ferromagnetism upon thermal annealing in pure ZnO

被引:261
作者
Banerjee, S.
Mandal, M.
Gayathri, N.
Sardar, M.
机构
[1] Saha Inst Nucl Phys, Surface Phys Div, Kolkata 700064, W Bengal, India
[2] Saha Inst Nucl Phys, Div Chem Sci, Kolkata 700064, W Bengal, India
[3] Indira Gandhi Ctr Atom Res, Div Mat Sci, Kalpakkam 603102, Tamil Nadu, India
关键词
D O I
10.1063/1.2804081
中图分类号
O59 [应用物理学];
学科分类号
摘要
We report here the enhancement of ferromagnetism in pure ZnO upon thermal annealing with the ferromagnetic transition temperature T-c above room temperature. We observe a finite coercive field up to 300 K and a finite thermoremanent magnetization up to 340 K for the annealed sample. We propose that magnetic moments can be formed at anionic vacancy clusters. Ferromagnetism can occur due to either superexchange between vacancy clusters via isolated F+ centers or through a limited electron delocalization between vacancy clusters. Isolated vacancy clusters or isolated F+ centers give rise to a strong paramagneticlike behavior below 10 K. (C) 2007 American Institute of Physics.
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