Structural, dielectric and ferroelectric study of microwave sintered lanthanum substituted BaTiO3 ceramics

Lanthanum substituted barium titanate (BT), Ba(1−x)LaxTi(1−x/4)O3 (where x = 0.02,0.04,0.06 and 0.08)/BLT1, BLT2, BLT3 and BLT4 ferroelectric ceramic samples were synthesized in single perovskite phase by microwave (MW) processing technique. Dense packing of grains with higher density at lower sintering temperature (1100 °C) signifies the importance of MW process over conventional process. The structure changes from tetragonal to cubic and grain size gradually decreases with the increase in La3+ ions substitution concentration in BT ceramic samples. Presence of pore free uniform grains suggested the advantage of using microwave sintering process. Transition temperature (Tc) decreases with the increase in La3+ ions substitution concentration in BT system and for BLT3 and BLT4 systems Tc is below room temperature (RT). Temperature coefficient of capacitance is negligible from RT temperature to 75 °C and 50 °C for BLT1 and BLT2 ceramic samples, respectively. Ferroelectric study confirms the transformation of structure from tetragonal to cubic with the increase of La3+ ion substitution concentration in BT system.