Microstructural and high temperature dielectric, ferroelectric and complex impedance spectroscopic properties of BiFeO3 modified NBT-BT lead free ferroelectric ceramics

Solid solutions of nano structured Na0.5Bi0.5TiO3-Ba0.925Nd0.05TiO3-BiFeO3 (0.7NBT-0.2BT1-0.1BF & 0.7NBT-0.1BT1-0.2BF) compositions were prepared by the conventional sol-gel method and the effect of BiFeO3 addition on microstructure, dielectric, ferroelectric and high temperature electrical properties of NBT-BT1-BF ceramics were investigated through XRD, SEM, dielectric and electrical characterization. X-ray diffraction patterns are well indexed and found that samples are crystallized in rhombohedral phase. SEM images have shown uniform distribution of grains and change in grain size with BiFeO3 concentration. The samples exhibited relaxor behavior, which is accompanied by a shift in εmax and Z'' towards high temperature with increasing BiFeO3 concentration. The grain and grain boundary response as well as the relaxation processes at different frequencies and temperatures were discussed. These observations suggest that BiFeO3 addition to NBT-BT1 ceramics can be considered as a potential lead free ceramic system in multi-ferroic devices.