Barkhausen noise in a relaxor ferroelectric

Barkhausen noise in the relaxor regime of a relaxor ferroelectric, PbMg_1/3Nb_2/3O₃ (PMN), was analyzed. The sample was grown by Chokhralsky method from a PMN single crystal. Two halves of PMN sample were incorporated in a balanced-bridge circuit to perform noise measurements. Analysis suggested that the noise consisted of periodically repeated random walk for periodically driven fields. Temperature dependence of amplitude and spectral form suggested that size of coherent change in dipole moment shrinked as the relaxor regime was entered.