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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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|
|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|
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