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Exchange bias and the origin of room-temperature ferromagnetism in Fe-doped NiO bulk samples

Authors :
K.L. Liu
C. H. Wang
Y. S. Yin
Yan Wang
Zhaoming Tian
Peng Li
Jinghua He
Songliu Yuan
Source :
Journal of Applied Physics. 103:023906
Publication Year :
2008
Publisher :
AIP Publishing, 2008.

Abstract

A series of Ni(1−x)FexO (x=0, 0.015, 0.03, 0.05, and 0.1) bulk samples was synthesized by the chemical concentration-precipitation method. Phase composition analysis was carried out, which showed that trace amounts of ferromagnetic phase NiFe2O4 could not be detected by x-ray diffraction in these bulk samples with x≤0.03. When x>0.03, NiFe2O4 ferrite is detected easily. The magnetic properties of all the bulk samples were investigated by measuring their magnetization as a function of temperature and magnetic field. The results indicated that all the bulk samples sintered in air exhibited large room-temperature ferromagnetic behavior ascribed to a ferromagnetic impurity phase. Simultaneously, an exchange bias and training effect were also observed in all the bulk samples, suggesting the possibility of the existence of a strong ferromagnetic/antiferromagnetic exchange coupling in this kind of compound. Specifically, the exchange bias field could be tuned by changing the concentration of the Fe dopant.

Details

ISSN :
10897550 and 00218979
Volume :
103
Database :
OpenAIRE
Journal :
Journal of Applied Physics
Accession number :
edsair.doi...........14d8bba0f35e8040bb867bae0121d608