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arXiv · 1803.09881

Magneto-Electric Effect in a Spin-State Transition System

Makoto Naka·Eriko Mizoguchi·Joji Nasu·Sumio Ishihara
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Abstract

Magnetic, dielectric, and magnetoelectric properties in a spin-state transition system are examined, motivated by the recent discovery of a multiferroic behavior in a cobalt oxide. We construct an effective model Hamiltonian based on the two-orbital Hubbard model, in which the spin-state degrees of freedom in magnetic ions couple with ferroelectric-type lattice distortions. A phase transition occurs from the high-temperature low-spin phase to the low-temperature high-spin ferroelectric phase with accompanying an increase of the spin entropy. The calculated results are consistent with the experimental pressure-temperature phase diagram. We predict the magnetic-field induced electric polarization in the low-spin paraelectric phase near the ferroelectric phase boundary.

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Makoto Naka, Eriko Mizoguchi, Joji Nasu, Sumio Ishihara. 2018-03-27. Magneto-Electric Effect in a Spin-State Transition System. https://doi.org/10.7566/jpsj.87.063709

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