Crystallographic characterization and microstructure study of perovskite phase : CaTi1-x(Fe0.5Nb0.5)xO3 (x=0.1-1.0)

Perovskite phases of iron and niobium substituted calcium titanate (hereafter CTFN) have been synthesized by a combination of precursor and ceramic method. The crystal structure of CaTi1-x(Fe0.5Nb0.5)(x)O-3 (x = 0.1-1.0) phases has been investigated using General Structure Analysis System (GSAS) programming. These phases crystallize in the orthorhombic system with space group Pbnm and Z = 4. Approximately 12 mole% of cations could be loaded into the matrix without significant changes of the three-dimensional framework structure. Powder diffraction data have been subjected to Rietveld refinement to arrive at a satisfactory convergence of R-factors. The unit cell parameters and cell volume increase regularly with increasing level of substitution on titanium site. The polyhedral distortions and bond valence calculation based on bond strength analysis have been reported. Morphology of the samples has been investigated by SEM and TEM analysis. Frequency dependent dielectric behavior of the material has been observed.