Pressure-induced phase transition and electrical properties of yttrium-doped polycrystalline BaTiO3

The electrical transport properties of undoped and 2% yttrium-doped polycrystalline BaTiO3 (BTY0 and BTY2) at high temperature and high pressure were studied using a diamond-anvil cell in conjunction with AC impedance spectroscopy up to & SIM;20 GPa. The BTY0 endured a ferroelectric-paraelectric transition at & SIM;5 GPa, and a & SIM;2 GPa ahead of the transition point was observed in BTY2. We found that the doping of 2% Y ions in BTY2 leads to a decrease in the Curie transition temperature. For both BTY0 and BTY2, an increase in pressure will result in a significant reduction in the Curie temperature and the decreasing rate gradually decreased under pressure. The reducing grain size of the sample and the effect of the deviatoric stresses are considered as the main factors causing the decrease of dT(C)/dP.