Models for spin-state transitions in solids

Ramasesha, S and Ramakrishnan, TV and Rao, CNR (1979) Models for spin-state transitions in solids. In: Journal of Physics C: Solid State Physics, 12 (7). pp. 1307-1317.

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Abstract

The model for spin-state transitions described by Bari and Sivardiere (1972) is static and can be solved exactly even when the dynamics of the lattice are included; the dynamic model does not, however, show any phase transition. A coupling between the octahedra, on the other hand, leads to a phase transition in the dynamical two-sublattice displacement model. A coupling of the spin states to the cube of the sublattice displacement leads to a first-order phase transition. The most reasonable model appears to be a two-phonon model in which an ion-cage mode mixes the spin states, while a breathing mode couples to the spin states without mixing. This model explains the non-zero population of high-spin states at low temperatures, temperature-dependent variations in the inverse susceptibility and the spin-state population ratio, as well as the structural phase transitions accompanying spin-state transitions found in some systems.

Item Type:	Journal Article
Publication:	Journal of Physics C: Solid State Physics
Publisher:	Institute of Physics
Additional Information:	Copyright of this article belongs to Institute of Physics.
Department/Centre:	Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited:	27 Dec 2010 04:54
Last Modified:	27 Dec 2010 04:54
URI:	http://eprints.iisc.ac.in/id/eprint/34273

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