Thermal, structural and complex impedance analysis of Mn4+ modified BaTiO3 electroceramic

The polycrystalline samples of BaTi1−xMnxO3 (BMT) ferroelectric ceramics with x=0, 0.04, 0.07, 0.10 have been prepared using a solid-state reaction technique. The calcination temperature of the samples was optimized by thermal gravimetric analysis and repeated firing. Preliminary structural study using X-ray diffraction technique at room temperature suggests that structure of Mn modified compounds (BMT) change into orthorhombic crystal system from tetragonal crystal system. The field emission scanning electron micrographs (FE-SEM) show uniform grain distribution throughout the surface of the samples. Complex impedance analysis (CIS) has been carried out to investigate the electrical properties of BMT. The real and imaginary part of complex impedance plots exhibit semicircle(s) in the complex plane. The bulk resistance of the material decreases with rise in temperatures similar to a semiconductor. The variation of bulk ac conductivity with frequency shows that the compounds exhibit dispersive type electrical conductivity.