Infrared, terahertz, and microwave spectroscopy of the soft and central modes in Pb(Mg_1/3Nb_2/3)O₃

From the new infrared (IR) reflectivity and time-domain terahertz spectra combined with available high-frequency dielectric data above the megahertz range in a broad temperature range of 10 to 900 K, a full picture of the soft- and central-mode behavior in the classical relaxor ferroelectric Pb(Mg_1/3Nb_2/3)O₃ (PMN) is suggested. A detailed comparison is made with the recent hyper-Raman spectroscopy data [Hehlen et al., Phys. Rev. Lett. 117, 155501 (2016)] and also with other available experiments based on inelastic light and neutron scattering. It is revealed that each type of experiment provides slightly different data.

Temperature dependencies of two components in soft-mode PMN from terahertz and infrared spectra.

¹Institute of Physics, Czech Academy of Sciences, Na Slovance 2, 182 21 Prague 8, Czech Republic
²Laboratoire Charles Coulomb (L2C), UMR 2251, CNRS-Université de Montpellier, F-34095 Montpellier, France