Effects of Mn-dopant on phase, microstructure and electrical properties in Bi3.25La0.75Ti3O12 ceramics

Lanthanum-doped bismuth titanate (Bi3.25La0.75Ti3O12 or BLT) is important ferroelectric materials for FeRAMS, which need further improved by substituting isovalent cations to assist the elimination of defects such as oxygen vacancy. In this work, fabrication and investigation of substituting Mn4+ for Ti4+ ion on B-site of Bi3.25La0.75Ti3O12 ceramics were carried out. X-ray diffraction patterns of BLTMn ceramics indicated orthorhombic structure with lattice distortion, especially for samples with higher concentration of MnO2 dopant. Microstructural investigation showed that all ceramics composed mainly of plate-like grains. An increase in MnO2 doping content increased diameter and thickness of grains but reduced density of the ceramics. Electrical conductivity was found to decrease while dielectric constant increased with Mn4+ doping concentration.