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Spin-state transition in LaCoO3: direct neutron spectroscopic evidence of excited magnetic states

A. Podlesnyak·S. Streule·J. Mesot·M. Medarde·E. Pomjakushina·K. Conder·M. W. Haverkort·D. I. Khomskii
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Abstract

A gradual spin-state transition occurs in LaCoO3 around T~80-120 K, whose detailed nature remains controversial. We studied this transition by means of inelastic neutron scattering (INS), and found that with increasing temperature an excitation at ~0.6 meV appears, whose intensity increases with temperature, following the bulk magnetization. Within a model including crystal field interaction and spin-orbit coupling we interpret this excitation as originating from a transition between thermally excited states located about 120 K above the ground state. We further discuss the nature of the magnetic excited state in terms of intermediate-spin (IS, S=1) vs. high-spin (HS, S=2) states. Since the g-factor obtained from the field dependence of the INS is g~3, the second interpretation looks more plausible.

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A. Podlesnyak, S. Streule, J. Mesot, M. Medarde, E. Pomjakushina, K. Conder, M. W. Haverkort, D. I. Khomskii. 2005-05-14. Spin-state transition in LaCoO3: direct neutron spectroscopic evidence of excited magnetic states. https://doi.org/10.1103/physrevlett.97.247208

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