Spin state transition in LaCoO3 studied using soft x-ray absorption spectroscopy and magnetic circular dichroism
Spin state transition in LaCoO3 studied using soft x-ray absorption spectroscopy and magnetic circular dichroism
复制标题
DOI：
10.1103/physrevlett.97.176405
复制
发表时间：
2006-10-27
影响因子：
8.6
通讯作者：
Tjeng, L. H.
中科院分区：
文献类型：
--
作者：
Haverkort, M. W.;Hu, Z.;Tjeng, L. H.
用软X射线吸收谱和Co-L-2，L-3边的磁性圆二色谱揭示了LaCoO_3的自旋态转变可以用低自旋基态和三重简并高自旋第一激发态来很好地描述。从谱线形状对温度的依赖关系，我们发现LaCoO_3在有限温度下是一个非均匀的混合自旋态系统。顺磁态的磁性圆二色信号携带较大的轨道动量是至关重要的。这直接表明目前公认的低自旋或中自旋图景是不一致的。从这些光谱得到的参数充分解释了现有的磁化率、电子自旋共振和非弹性中子数据。
Using soft x-ray absorption spectroscopy and magnetic circular dichroism at the Co-L-2,L-3 edge, we reveal that the spin state transition in LaCoO3 can be well described by a low-spin ground state and a triply degenerate high-spin first excited state. From the temperature dependence of the spectral line shapes, we find that LaCoO3 at finite temperatures is an inhomogeneous mixed-spin state system. It is crucial that the magnetic circular dichroism signal in the paramagnetic state carries a large orbital momentum. This directly shows that the currently accepted low- or intermediate-spin picture is at variance. Parameters derived from these spectroscopies fully explain existing magnetic susceptibility, electron spin resonance, and inelastic neutron data.