Dielectric properties of Mn-doped (Na0.8K0.2)0.5Bi0.5TiO3 ceramics

In this paper, the lead-free ceramics with single perovskite phase of (Na0.8K0.2)0.5Bi0.5TiO3 + x wt.% Mn (abbreviated as BNKT-x% Mn, x = 0∼0.5) were prepared by solid state reaction method. The SEM indicates that Mn-doping restrains the growth of grain at a certain extent. There were two abnormal dielectric peaks of Td and Tm appeared in curves of dielectric permittivity vs. temperature for the pure BNKT ceramics. Compared to pure BNKT ceramics, Mn-doping restrained the transition of ferroelectric phase to antiferroelectric phase that can be explained by oxygen vacancies. A linear fitting of the modified Curie–Weiss law to experimental data show that all the samples have a diffuse character.