Giant dielectric and ferromagnetic response in Ba 0.4 Sr 0.6 Ti 1− y Co y O 3 ceramics

Ba 0.4 Sr 0.6 Ti 1− y Co y O 3 ceramics show a diphase of Ba 1− x Sr x TiO 3 and 6H‐hexagonal BaTi 1− y Co y O 3 . As y increases, Ba 0.4 Sr 0.6 Ti 1− y Co y O 3 ceramics experience a transformation from ferroelectric to relaxor‐like behavior. For the samples with y  ≥ 0.10, the dielectric constant exhibits relaxor‐like behavior with the frequency‐dependent temperature of the dielectric peak T m following an Arrhenius law, accompanying a giant dielectric response. The dielectric relaxation with an extremely high dielectric peak is attributed to charge ordering and defects. The samples with low Co levels ( y  ≤ 0.05) exhibit dielectric nonlinear behavior, whereas those with high Co levels ( y  ≥ 0.10) have ferromagnetic properties.