Dielectric properties of K1-x Lix TaO3 at frequencies 10-2 - 103 Hz

Abstract

Dielectric spectrum ε*(ν) = ε(ν) + iε''(ν) and hysteresis loops P(E) have been studied as functions of frequency ν and temperature T in single crystals of K1-x Lix TaO3 with x = 0.10 and 0.15. The position of ε''(T) maximum is shifted to low temperatures as the frequency decreases. In the low-temperature phase (T < T0) the saturated hysteresis loops P(E) are observed. The coercive field and spontaneous polarization increase with cooling of the sample. There are two relaxation regions of ε*(ν) in Cole-Cole plots. The first one is for 10-103 Hz and the second one is for 10-2-103 Hz.On the basis of these experimental data we conclude that the low-temperature phase in K1-x LixTaO3 has a ferroelectric nature rather than polar glass one.