Spin-State Transition in LaCoO3 : Direct Neutron Spectroscopic Evidence of Excited Magnetic States
PhysRevLett_97_247208.pdf 387 KB
Haverkort, Maurits W.
A gradual spin-state transition occurs in LaCoO3 around T∼80-120K, whose detailed nature remains controversial. We studied this transition by means of inelastic neutron scattering and found that with increasing temperature an excitation at ∼0.6meV 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 120K above the ground state. We further discuss the nature of the magnetic excited state in terms of intermediate-spin (t2g5eg1, S=1) versus high-spin (t2g4eg2, S=2) states. Since the g factor obtained from the field dependence of the inelastic neutron scattering is g∼3, the second interpretation is definitely favored.
Physical Review Letters
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American Physical Society
Copyright (c) 2006 The American Physical Society.
Graduate School of Advanced Sciences of Matter