Dynamical Properties of Polar Nanoregions of Relaxor Ferroelectric Pb(Ni_<1/3>Nb_<2/3>)O_3-0.29PbTiO_3(Condensed matter: electronic structure and electrical, magnetic, and optical properties)

概要

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Dynamical properties of the polar nanoregions (PNRs) of a relaxor ferroelectric Pb(Ni_<1/3>Nb_<2/3>)O_3-0.29PbTiO_3 single crystal are studied by using Brillouin scattering to elucidate the mechanism of the diffuse phase transition. The temperature dependence of Brillouin scattering shows anomalies at three temperatures: at T_d related to the appearance of the PNRs, at T^* associated with the growth of the PNRs, and at T_f related to the macroscopic structural phase transition; all these temperatures are closely related to the dynamical behavior of the PNRs. The thermal hysteresis around T_f in the longitudinal acoustic properties can be interpreted by considering the growth process of the PNRs. From the anomalous acoustic properties, the relaxation time of the polarization fluctuation is evaluated. It is found that the relaxational process responsible for the central peak originates from the polarization fluctuation that is coupled with the longitudinal acoustic mode.
社団法人日本物理学会の論文
2008-03-15