Manifestation of freezing in the nonlinear dielectric response of PMN relaxor system

Abstract

Dependence of the dielectric nonlinearity a₃ on temperature has been determined in PMN single crystal. A crossover from the decreasing paraelectric-like to the increasing glass-like temperature behavior has been observed in the static a₃ on cooling towards the freezing transition in the absence of electric field. It is shown that this crossover is actually predicted by the spherical random bond-random field model of relaxor ferroelectrics. Results support the idea that relaxor systems, at zero electric field undergo a transition into a low-temperature glassy state.

Key Words:

• Relaxor
• PMN
• nonlinear dielectric constant.