Phase transition and electric properties of (1 − x)BaTiO3–xSr1.9Ca0.1NaNb5O15 perovskite solid solutions

Abstract

(1 − x)BaTiO3–xSr1.9Ca0.1NaNb5O15 [(1 − x)BT–xSCNN, 0 ≤ x ≤ 0.05] ceramics were prepared by conventional solid-state processing technique. Lorentzian function was used to fit the diffraction lines of the X-ray diffraction patterns, and obtained a structural phase transition from tetragonal to rhombohedral. The structural parameters were refined by the Rietveld method using Maud software from the X-ray diffraction patterns of BT–SCNN ceramics. The lattice parameters were found to decrease with increasing the concentration of SCNN. From the Arrhenius plots, the calculated activation energies of the relaxation and the conduction indicated that both the relaxation processes and conduction were thermally activated, and oxygen vacancies were the possible ionic charge carriers at high temperatures. The polarization study revealed a well-saturated hysteresis loop.