Finite size effects in antiferromagnetic NiO nanoparticles

被引:823
作者
Kodama, RH
Makhlouf, SA
Berkowitz, AE
机构
[1] UNIV CALIF SAN DIEGO, CTR MAGNET RECORDING RES, LA JOLLA, CA 92093 USA
[2] ASSIUT UNIV, DEPT PHYS, ASSIUT 71516, EGYPT
关键词
D O I
10.1103/PhysRevLett.79.1393
中图分类号
O4 [物理学];
学科分类号
0702 ;
摘要
Antiferromagnetic NiO nanoparticles exhibit anomalous magnetic properties, such as large moments, and coercivities and loop shifts of up to 10 kOe. This behavior is difficult to understand in terms of 2-sublattice antiferromagnetic ordering which is accepted for bulk NiO. Numerical modeling of spin configurations in these nanoparticles yields 8-, 6-, or 4-sublattice configurations, indicating a new finite size effect, in which the reduced coordination of surface spins causes a fundamental change in the magnetic order throughout the particle. The relatively weak coupling between the sublattices allows a variety of reversal paths for the spins upon cycling the applied field, resulting in large coercivities and loop shifts.
引用
收藏
页码:1393 / 1396
页数:4
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