Ferroelectric soft mode in Pb(Mg1/3Nb2/3)O3 (PMN) has been clearly resolved by precision Raman scattering measurements for the first time. A polarization direction of the incident laser was chosen along [110] in cubic configuration in order to eliminate strong scattering components around 45 cm-1, which always smeared the low-frequency spectra of PMN. The soft mode frequency omega_s (=\sqrt{omega_0^2-gamma^2}) softens around 200 K, where omega_0 and gamma are a harmonic frequency and a damping constant, respectively. The present result evidenced that the origin of the polarizationthe in PMN is the soft mode.
@article{arxiv.0909.3889,
title = {Ferroelectric Soft Mode in Pb(Mg1/3Nb2/3)O3},
author = {Hiroki Taniguchi and Masanori Oishi and Desheng Fu and Mitsuru Itoh},
journal= {arXiv preprint arXiv:0909.3889},
year = {2009}
}