Electrical and structural characteristics of lanthanum-doped barium titanate ceramics

摘要: Single phase La-doped BaTiO3 with the formula Ba1−xLaxTi1−x/4O3: 0⩽x⩽0.20 was prepared by solid state reaction of oxide mixtures at 1350 °C, 3 days, in O2. The tetragonal distortion undoped decreased x and samples were cubic for x⩾0.05. Both tetragonal/cubic orthorhombic/tetragonal transition temperatures x, but different rates, appeared to coalesce x∼0.08. value permittivity maximum ceramic increased from ∼10 000 x=0 130 °C ∼25 000 x=0.06 ∼−9 °C. At larger broadened, showed “relaxor”-type frequency dependent characteristics continued move lower temperatures. Samples fired O2 insulating no signs donor doping whereas air-fired semiconducting, attributable oxygen loss.