Spin State Transition in LaCoO3 Studied Using Soft X-ray Absorption Spectroscopy and Magnetic Circular Dichroism
PhysRevLett_97_176405.pdf 560 KB
Haverkort, Maurits W.
Cezar, Júlio C.
Brookes, Nicholas B.
Tjeng, L. Hao
Using soft x-ray absorption spectroscopy and magnetic circular dichroism at the Co-L2,3 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.
Physical Review Letters
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American Physical Society
Copyright (c) 2006 The American Physical Society.
Graduate School of Advanced Sciences of Matter