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 degrees 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 (T-c) decreases with the increase in La3+ ions substitution concentration in BT system and for BLT3 and BLT4 systems T-c is below room temperature (RT). Temperature coefficient of capacitance is negligible from RT temperature to 75 degrees C and 50 degrees 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. (C) 2011 Elsevier B.V. All rights reserved.