Magnetoelectric, spectroscopic, optical and elastic properties of Co-doped BaTiO₃ ceramics

The BaTiO₃ perovskite is widely used in the electronic technology due to its dielectric, piezoelectric and ferroelectric properties and is a well-known base for obtaining a promising multifunctional material. In this paper we report the extensive studies on the Co-doped BaTiO₃ ceramics for the wide range cobalt content. Full structural characterization of studied samples in a 20–450 K range was provided. The results of research on spectroscopic, dielectric, electronic, optical, magnetic and elastic properties are presented. The superior dielectric properties to those exhibited by the parent compound have been found. Namely, the reduction of dielectric losses and stability of the dielectric permittivity in the vicinity of the room temperature are reported. Additionally, our research revealed: broadening of the dielectric anomalies related to the ferroelectric-paraelectric phase transition, shifting the Curie point towards lower temperatures, displacive mechanism of Curie phase transition with order-disorder contributions; maximum value of the real part of dielectric permittivity of about 5000 at Curie point for 0.05 wt% of Co-doping, value of the activation energy ∼ 0.9 eV as the result of the migration of oxygen vacancies that are generated due to charge compensation, and the occurrence of magnetoelectric response. At last, the Co-doped BaTiO₃ shows potential to use in non-linear optoelectronic devices, while no evidence of multiferroic properties, suggested in the literature, was found.