Ferroelectric Properties of Pb(Zn_1⁄3Nb_2⁄3)O₃

Abstract

The ferroelectric properties of a single crystal of Pb(Zn_1⁄3Nb_2⁄3)O₃ were investigated in the ferroelectric and paraelectric temperature regions. The crystal undergoes a ferroelectric phase transition in a wide temperature range, changing from cubic perovskite structure to rhombohedral one. A broad peak was observed in the dielectric constant vs temperature curve, being characteristic of the disordered perovskite ferroelectrics. The spontaneous polarizations were obtained from the hysteresis loop and the pyroelectric current, and there was found a discrepancy in both measurements. Without applying an electric field the optical anisotropy was not detected. But with the field the domain and the birefringence were observed. The effects of the d.c. field on the dielectric constant and the birefringence were observed over the wide temperature range. A brief explanation of the character of the phase transition as well as dielectric and optical properties were given.