Observation of long range correlation dynamics in BaTiO3 near TC by photon correlation spectroscopy

Long range correlation dynamics of polarization clusters in BaTiO3 have been observed directly near the Curie temperature (T-C) by photon correlation spectroscopy. A correlation length on the order of 200 nm was found to be dynamic near T-C with a characteristic relaxation time of several microseconds. This relaxation time decreased with an increase in temperature, but exhibited an anomaly at T-C, indicating the dominating contribution to the dielectric permittivity by these polarization clusters near T-C.