HR: 11:26h
AN: MR22A-06    [Abstracts]
TI: Dynamical effect of the spin transition: A numerical simulation study
AU: * Tsuchiya, T
EM: takut@sci.ehime-u.ac.jp
AF: Geodynamics Research Center, Ehime University, 2-5 Bunkyo-cho, Matsuyama, 790-8577, Japan
AU: Tsuchiya, J
EM: junt@sci.ehime-u.ac.jp
AF: Geodynamics Research Center, Ehime University, 2-5 Bunkyo-cho, Matsuyama, 790-8577, Japan
AB: Recent progresses in mineral physics have revealed several new phenomena under high-P,T conditions which likely affect chemical and physical properties of the Earth's lower mantle. In particular, spin transition of iron in the mantle minerals is one of the quaintest and also most important. Theoretical free energy modelling conbining with density functional computation proposed broad pressure region where high-spin and low-spin iron coexist along the mantle geotherm. Across this high-spin/low-spin mixed state, any properties are expected to vary continuously. This transient area is also confirmed experimentally. However, the dynamical effect of the spin crossover is still little understood. In this study, we have performed thousands atom numerical simulations to model the mixed spin state. Calculations suggest important consequences that the spin transition is accompanied by anomalous behaviors driven by dynamical fluctuation of spin state even though the structure remains macroscopically isosymmetric. Research supported by the Ehime Univ Project Fund and in part by JSPS.
DE: 1025 Composition of the mantle
DE: 1212 Earth's interior: composition and state (7207, 7208, 8105, 8124)
DE: 3909 Elasticity and anelasticity
DE: 3924 High-pressure behavior
SC: Mineral and Rock Physics [MR]
MN: 2007 Fall Meeting