Nonlinear dynamics of polar regions in paraelectric phase of (Ban_(1-x),Sr_x)TiO_3 ceramics

摘要

The dynamic dielectric nonlinearity of barium strontium titanate (Ba_(1-x),Sr_x)TiO_3 ceramics is investigated in their paraelectric phase. With the goal to contribute to the identification of the mechanisms that govern the dielectric nonlinearity in this family, we analyze the amplitude and the phase angles of the first and the third harmonics of polarization. Our study shows that an inteipretation of the field-dependent polarization in paraelectric (Ba_(1-x)Sr_x)TiO_3 ceramics in terms of the Rayleigh-type dynamics is inadequate for our samples and that their nonlinear response rather resembles that observed in canonical relaxor Pb(Mg_(1/3)Nb_(2/3))O_3.