Evidence of macro-micro domain transition in poled PMN-PZT ceramics

The dielectric properties of unpoled and poled Pb0.88Ba0.06Sr0.06(Mg1/3Nb2/3)0.37Zr0.375Ti0.255O3 (modified PMN-PZT) ceramics were investigated. It was found that the dielectric constant increased while the loss tangent decreased after poling. A frequency independent abrupt transition in the dielectric constant and loss tangent responses was observed for the poled ceramics. This abnormal behavior was believed to be correlated with the macro-micro domain transition and the corresponding pyroelectric measurement exhibited a narrow peak at the normal-relaxor transition temperature Tnr. Furthermore, the presence of double-loop-like hysteresis and two types of current peaks at a temperature slightly higher than Tnr showed another strong evidence of this transition.