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

Abstract In this paper, the lead-free ceramics with single perovskite phase of (Na 0.8 K 0.2 ) 0.5 Bi 0.5 TiO 3 + 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 T d and T m 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.