Dielectric Properties and Phase Diagram of (Sr_1-xBa_x)₂Nb₂O₇Single Crystals

Dielectric constants, εb′ and εc′ along the crystallographic b and c axes respectively, were measured in a temperature range of 10 − 700 K on Ba-substituted Sr2Nb2O7 single crystals with different Ba concentrations up to x = 0.32. When x = 0, two dielectric anomalies were observed at TI = 489 K and at TL = 100 K, owing to the incommensurate phase transition and the low-temperature ferroelectric phase transition, respectively. Both TI and TL...