A high dielectric permittivity and strong Ba-vacancy defects of (Ba<inf>1–</inf><inf>x</inf>Sm<inf>x</inf>)(Ti<inf>1–(</inf><inf>x</inf><inf>–0.01)</inf>Co<inf>x</inf><inf>–0.01</inf>)O<inf>3</inf> ceramic

Abstract

(Ba1–xSmx)(Ti1–xCox)O3, (Ba1–xSmx)(Ti1–(x–0.01)Cox–0.01)O3 and Ba(Ti1−xCox)O3 ceramics were synthesized using a traditional solid-state based method. All series of ceramics have a structural evolution. Sm3+ as donors into Ba2+ sites could suppress the formation of hexagonal phase effectively and improve dielectric properties. Particularly a cubic ceramic (Ba1–xSmx)(Ti1–(x–0.01)Cox–0.01)O3 with x = 0.05 met the EIA Y5V specification with a higher room-temperature dielectric permittivity (ε′RT = 3955). A stronger EPR signal (g = 1.974) was attributed to ionized Ba-vacancy (VBa′′), was surprisingly observed in (Ba1–xSmx)(Ti1–(x–0.01)Cox–0.01)O3 (Ba/Ti > 1), which is extremely rare among rare-earth-doped BaTiO3 ceramics, suggests that Sm3+ ions behaved with an amphoteric nature. Interest was paid to analyze defect chemistry associated with amphoteric Sm ions and valence-variable Co ions (3+ and 4+).