Low temperature Schottky anomalies in the specific heat of LaCoO3: Defect-stabilized finite spin states

He, C.; Zheng, H.; Mitchell, J. F.; Foo, M. L.; Cava, R. J.; Leighton, C.
March 2009
Applied Physics Letters;3/9/2009, Vol. 94 Issue 10, pN.PAG
Academic Journal
Measurement of the low temperature specific heat of LaCoO3 single crystals reveals a previously unobserved Schottky anomaly with an energy level splitting, 0.5 meV, that is associated with the first excited spin state of the Co3+ ion. These states persist well below 2 K and have a g-factor around 3.5, consistent with the high-spin spin-orbit triplet, implying the existence of a low density (approximately 0.1% of the sites) of finite-spin Co ions even in the T=0 limit. We propose that these states are trapped at defects and are consistent with the magnetic excitons observed in earlier work.


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