Improvement of energy storage properties with the reduction of depolarization temperature in lead-free (1 – x)Na0.5Bi0.5TiO3-xAgTaO3 ceramics

The effects of electric field and temperature on structural, dielectric, and ferroelectric properties of (1 – x)(Na0.50Bi0.50TiO3)-xAgTaO3 (x = 0, 0.03, 0.05, and 0.10) ceramics prepared via the modified sol-gel method were investigated. Rietveld refinement of synchrotron radiation x-ray diffraction data (SRPXRD) confirmed the rhombohedral (R3c) phase in all the unpoled samples. After poling, the samples remained in the rhombohedral phase for x ≤ 0.03, whereas for x ≥ 0.05, it showed a mixed rhombohedral and tetragonal (P4bm) phase. The anti-phase octahedral tilt angle was found to increase from 8.49° to 9.50° (for x = 0) and from 7.60° to 7.85° (for x = 0.10) with poling due to the long-range ordering phenomenon in the lattice system. The temperature-dependent dielectric study showed that the depolarization temperature decreases with increasing composition. Unpoled x = 0.10 composition exhibited the wide thermal stability dielectric constant in the temperature range 120-450 °C with 1795 ± 15% (tan δ < 0....