Dielectric response of PMN-0.32PT single crystal and ceramics under dc electric field

The temperature dependences of dielectric properties for [001] PMN-0.32PT single crystal and PMN-0.32PT ceramics under different de electric field (E) have been investigated. A new monoclinic phase can be induced by electric field with E = 1.5-4.0 kV/cm, while heating, in [001] PMN-0.32PT single crystal. The phase transition process of single crystal'is from rhombohedral to monoclinic, then from monoclinic to tetragonal, finally from tetragonal to cubic. With increasing electric field, all of the phase transition temperatures increased in the single crystal. Comparing with single crystal, no new phase is induced by electric field and temperature field in PMN-0.32PT ceramics. Similar to single crystal, the phase transition temperatures of PMN-0.32PT ceramics increased with increasing electric field. The difference of dielectric. response under dc electric field between two materials is discussed. The formation of new monoclinic phase results from polarization rotation from [111] to [001] direction under electric field in single crystal. (C) 2004 Elsevier Ltd and Techna Group S.r.l. All rights reserved.