Neutron diffraction study of a layered cobalt oxide SrCo6O11
Neutron diffraction study of a layered cobalt oxide SrCo6O11
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层状氧化钴 SrCo6O11 的中子衍射研究
DOI：
10.1016/j.jmmm.2006.10.602
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发表时间：
2007
影响因子：
2.7
通讯作者：
M. Takano
中科院分区：
文献类型：
--
作者：
Takashi Saito;A. Williams;J. Attfield;T. Wuernisha;T. Kamiyama;S. Ishiwata;Y. Takeda;Y. Shimakawa;M. Takano
采用中子衍射和Rietveld分析方法研究了六方层状氧化钴SrCo6O11在20K以下具有1/3的磁化平台和较大的负磁阻的磁性结构。已经发现，只有三角形双锥体位点具有局部力矩，对应于S=2，并且力矩沿c轴具有类似ising的各向异性。这些矩在c平面上以铁磁方式排列，而层间耦合则依赖于场。1/3的磁化平台反映了场致铁磁沿c轴的“up-up-down-up-up-down”排列。我们将这种复杂的自旋结构解释为最近的铁磁层之间的反铁磁超交换相互作用和载流子介导的铁磁相互作用的竞争。
The magnetic structure of a hexagonal layered cobalt oxide SrCo6O11, which exhibits a 1/3 magnetization plateau and a concomitant large negative megnetoresistance below 20K, was studied by means of neutron diffraction measurements and Rietveld analysis. It has been found that only the trigonal bipyramidal site carries a localized moment, which corresponds to S=2, and that the moment has an Ising-like anisotropy along the c-axis. These moments are aligned ferromagnetically in the c-plane, while the interlayer coupling is field dependent. The 1/3 magnetization plateau reflects a field-induced ferrimagnetic alignment along the c-axis like “up–up–down–up–up–down”. We interpret this complex spin structure as resulting from competition of an antiferromagnetic superexchange interaction between the nearest ferromagnetic layers and carrier-mediated, ferromagnetic interactions.