Structure of Ba(Y+31/2Ta+51/2)O3 and its dielectric properties in the range 102–1014 Hz, 20–600 K

The goal of this work was to understand the correlation between microscopic material parameters and the dielectric function of candidate materials for applications in the microwave frequency range. The structure and dielectric properties of Ba2+(Y3+1/2Ta5+1/2)O3 (BYT), a typical representative of the Ba(B3+1/2B5+1/2)O3 complex perovskite family, has been investigated from 102 to 1014 Hz and from 20 to 600 K. At Tc=253±1 K, BYT undergoes an equitranslational improper ferroelastic, second-order phase transition, characterized by the tilting of the oxygen octahedra. The space group symmetry changes from Fm3̄m, in the high temperature phase, to I4/m below Tc. The existence of an intermediate temperature region (Tc−40