Study on electrical properties of Ni-doped SrTiO_3 ceramics using impedance spectroscopy

摘要

The ceramics, SrTiO_3 (ST) and 0.4, 0.8 atom percent Ni doped SrTiO_3, were prepared by solid state reaction route. The average grain size of undoped and doped samples was measured and found to be 1.2,1.9 and 3.7 mu m, respectively. The impedance measurements were conducted at 400-600 deg C to separate grain and grain boundary contributions. The grain and grain boundaries relaxation frequencies were shifted to higher frequency with temperature. Bulk resistance of doped and undoped ST ceramics was more or less the same. Single grain boundary resistance of doped sample was higher than that of undoped one, indicating that GB resistance increases with acceptor doping. Activation energies were calculated to confirm the same,