Structural and magnetic properties of wurtzite CoO thin films

被引:21
作者
Alaria, J. [1 ]
Cheval, N. [1 ]
Rode, K. [1 ]
Venkatesan, M. [1 ]
Coey, J. M. D. [1 ]
机构
[1] Univ Dublin Trinity Coll, Sch Phys & CRANN, Dublin 2, Ireland
关键词
D O I
10.1088/0022-3727/41/13/135004
中图分类号
O59 [应用物理学];
学科分类号
摘要
Hexagonal CoO thin films on (0 0 0 1) Al2O3 and ZnO are prepared by off-axis and on-axis pulsed laser deposition. The structural properties were studied by in situ reflection high-energy electron diffraction and ex situ x-ray diffraction. The magnetic properties of the films depend on the mode of growth. The films grown in a normal geometry are a mixture of Co3O4 and CoO and show ferromagnetism at room temperature, whereas the films grown off-axis are single phase and present a Curie-Weiss behaviour. Wurtzite CoO does not order magnetically because the antiferromagnetic Co2+-O2--Co2+ superexchange is geometrically frustrated. It is proposed that defective Co3O4 in thin films is ferrimagnetic, due to the appearance of high spin Co3+ on B sites.
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页数:6
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