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Thermal conductivity of CaGeO 3 perovskite at high pressure
Author(s) -
Manthilake M. A. G. M.,
de Koker N.,
Frost D. J.
Publication year - 2011
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2011gl046882
Subject(s) - orthorhombic crystal system , thermal conductivity , perovskite (structure) , silicate perovskite , debye model , bulk modulus , materials science , phonon , thermodynamics , mineralogy , condensed matter physics , mantle (geology) , thermal conduction , debye , analytical chemistry (journal) , geology , crystal structure , chemistry , crystallography , physics , geophysics , chromatography
The pressure dependence of thermal conductivity () in Earth's lower mantle is poorly understood, resulting in very uncertain values in the D″. Using orthorhombic CaGeO 3 perovskite as an analogue for MgSiO 3 perovskite, we measured in a multi‐anvil apparatus using the Ångström method at pressures of 8, 10, 14 and 18 GPa, and temperatures of 573–1073 K. We find the pressure dependence of thermal conductivity for orthorhombic perovskite shows a somewhat higher slope than that predicted by Debye theory, and account for this by relating phonon velocities to the bulk modulus, rather than to the Debye temperature. From this relation, we estimate the thermal conductivity of MgSiO 3 perovskite at the top and bottom of the D″ to be 3.3 W/m K and 2.2 W/m K, corresponding to values of 6.4 W/m K and 4.5 W/m K for the mantle.