Effect of co-substitution of Sm3+ and Fe3+ ions on structural and dielectric properties of BaTiO3 ceramics

The material series of polycrystalline ferroelectric ceramics with compositional formula (Ba1-xSmx)(Ti1-xFex)O3 (with 0 ≥ x ≥ 0.01 in steps of 0.0025) was prepared by solid-state reaction method. The samples were sintered at 1300 °C (for x = 0) and 1325 °C for (x > 0). The sintered samples were subjected to X-ray diffraction (XRD) analysis and found to have single phase with tetragonal perovskite structure. Average grain size decreases with increase in substituent content. Dielectric behavior was studied as a function of temperature at different frequencies (1, 10,100,1000 kHz). The lattice constant 'c', tetragonality'c/a ratio' and Curie temperature 'Tc' was found to decrease with increase in the substituent content whereas the room temperature dielectric constant increases with substituent content. Large value of temperature coefficient of capacitance 'Tcc'> 10%/°C near Tc was observed for all the samples.