Anisotropic dielectric properties of PbYb1/2Ta1/2O3 single crystals

PbYb1/2Ta1/2O3 single crystals were obtained for the first time. They were grown by the flux method. The PbO-PbF2-B2O3 system was used as a solvent. Dielectric investigations were carried out in <1 0 0>c, <1 1 0>c and <1 1 1>c pseudocubic directions. These studies pointed to anisotropy of dielectric properties. Frequency-independent ε'(T) and ε''(T) maxima related to the antiferroelectric-paraelectric (AFE-PE) phase transition are observed for all directions at 562 K. The frequency-dependent ε'(T) and ε''(T) maxima near 400 K related to the ferroelectric (FE)-AFE phase transition are observed only in <1 1 1>c direction. The hysteresis loops were observed in this direction only. These results point that ferroelectric relaxor properties appear only in <1 1 1>c direction. We propose to consider the ferroelectric phase as ferrielectric one