Analysis of Structures and Order Parameters in Antiferroelectric PbHfO_3 Using Neutron Diffraction(Condensed matter: structure and mechanical and thermal properties)

概要

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We performed structural analysis of PbHfO_3 between 10 and 500K in the room-temperature antiferroelectric phase and the cubic phase using powder neutron diffraction. Disordered arrangements of Pb atoms were not detected in the cubic phase in contrast to the results of X-ray diffraction. This indicates that Pb atoms have an electron-density distribution that spreads out more widely than the expected distribution in isolated Pb ions. The simple concept of order parameters in soft-mode condensation, that is, all atomic shifts show proportional temperature dependences, was not observed in the antiferroelectric phase of PbHfO_3. However, physical properties, such as lattice distortion, show the temperature dependences predicted on the basis of a phenomenological theory as if the simple concept were applicable over the entire temperature range.
社団法人日本物理学会の論文
2008-06-15