Dilute ferroelectric in random electric field: Phase transitions in Pb(Mg_1/3Nb_2/3)_1-xTi_xO₃ crystals

Abstract

Phase transitions have been studied in single crystals of the ferroelectric solid solutions Pb(Mg_1/3Nb_2/3)_1-x Ti _x O₃ (PMN–PT) at 0 < x ≤ 0.2. An analysis of the low-frequency (10⁻¹–10⁻² Hz) hysteresis loops, the temperature dependence of the residual piezoelectric coefficient g ₁₁ = d ₁₁/χ₁₁ and the dielectric susceptibility χ₁₁ of polarized crystals established that PMN–PT becomes ferroelectric at low temperatures after going from a paraelectric Griffiths's phase through a nonpolar dipole glass phase with inhomogeneous long-range order and a partly polarized mixed phase. It has been shown that the unusual dielectric properties of PMN–PT in its low-temperature phases results from the appearance of a number of metastable states.

Key Words:

• Relaxor ferroelectrics
• phase transitions
• dipole glass
• hysteresis loops