Vogt, T.; Schmahl, Wolfgang W.
THE HIGH-TEMPERATURE PHASE-TRANSITION IN PEROVSKITE.
In: Europhysics Letters, Vol. 24, No. 4: pp. 281-285
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Perovskite (CaTiO3) is a model compound for the Earth’s most abundantmineral, the perovskite (Mg, Fe)SiO3. High-temperature structuralinvestigations using neutron powder diffraction reveal a phasetransition to a highly disordered cubic phase. As one approaches thistransition, the TiO6 octahedra become less distorted and theirrotational disorder is reflected by the large atomic-displacementparameters of the oxygens in the (a, b)-plane, suggesting that thehigh-temperature transition to the cubic phase could be triggered by theonset of mobility in the oxygen sublattice. This would account for thefact that no intermediate tetragonal phase is observed.