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 PbOPbF2B2O3 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.