Structure phase transitions of polymorphic compounds with layered crystal structures: The REIr(2)Si(2) case
2011
Abstrakt
REIr(2)Si(2) (RE = La, Ce, Pr and Nd) were found to be polymorphic compounds which can crystallize in two different tetragonal types of crystallographic structures (beta-phase: CaBe(2)Ge(2)-type; alpha-phase: ThCr(2)Si(2)-type). Here we study the structural phase transitions (alpha- to beta- and beta- to alpha-) using thermal expansion, differential thermal analysis and neutron diffraction.
Both phase transitions occur at temperatures lower than 1300 degrees C, have a hysteresis up to 300 degrees C, do not show any intermediate steps and are accompanied with the absorption/release of the latent heat. We conclude that these structural phase transitions are of the first order. (C) 2011 Elsevier Ltd.
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