Dielectric and thermal properties of lead magnesium niobate crystals above a middle curie temperature of diffuse ferroelectric phase transition

Publisher Website
Google Scholar
Abstract
Temperature dependences of dielectric constant, tgδ at frequencies ∼105 − 106 Hz and of thermal expansion along the pseudocubic directions {100}, {110} and {111} were studied at 300–900 K in the lead magnesium niobate (PMN) crystals. The differential thermoanalysis was carried out at 300–1270 K. Several anomalies in these temperature dependences were observed, some of them probably correspond to phase transitions. The diffuse antiferroelectric phase transition is supposed to occur near 650 K. The influence of this antiferroelectric phase transitions on diffuseness of the ferroelectric transition in PMN crystals is discussed.