Structure-dependent dielectric relaxations in Sm-doped BaTiO3 ceramics

Rare-earth Sm doped BaTiO3 ceramics were prepared by a solid-state reaction method, and the structures and dielectric properties were examined. Both tetragonality and phase-transition temperature decreased with increasing doping content. Colossal dielectric constant and dielectric relaxations were observed and were attributed to the inhomogeneous structure and interface-polarization effect. The multi-relaxation phenomenon depends on the doping content and reflects the complex inhomogeneity of the samples. The relaxation processes are closely related to the electrical resistances of the grain, and the activation energies depend on the crystal structures.