Dielectric and relaxation behaviors of (PbMg1/3Nb2/3O3)(0.67)(PbTiO3)(0.33) single crystal

Dielectric permittivity along the [111] direction has been measured as a fu nction of temperature for a relaxor ferroelectric single crystal (PbMg1/3Nb 2/3O3)(0.67)(PbTiO3)(0.33) (PMN-33%PT). A sharp ferroelectric phase transit ion was observed near 425 K and 429 K for cooling and heating processes, re spectively. As temperature decreases, a diffuse phase transition (which beg ins near 330 K upon cooling) was detected. In addition, the nature of the t hermal hysteresis for the dielectric permittivity confirms that these trans itions (near 330 and 425 K upon cooling) are diffuse first-order and first- order, respectively. The frequency-dependent dielectric data epsilon"(111)( f,T) prove the existence of an electric dipolar relaxation process between 350 and 400 K. The activation energy, the Vogel-Fulcher temperature and att empt frequency corresponding to this relaxation process are also calculated .