Dielectric and photoluminescence properties of fine-grained BaTiO3 ceramics co-doped with amphoteric Sm and valence-variable Cr

Abstract

(Ba_1−xSm_x)(Ti_1−xCr_x)O₃ (BSTC) and (Ba_1−xSm_x)(Ti_{1−(x−0.01)}Cr_x−0.01)O₃ (BSTC1) ceramics with a single-phase perovskite structure were prepared using a traditional solid state based method. The structure, microstructure, site occupations, valence states of Cr, photoluminescence, and dielectric properties of these ceramics were investigated using XRD, SEM, EDXS, RS, EPR, XPS, and dielectric measurements. All ceramics exhibit a fine-grained microstructure (0.7 μm). Three valence states of Cr ions were confirmed and Cr predominates as Cr³⁺ enter the Ti⁴⁺ sites with a stronger EPR signal (1.974). The RS bands of high-wavenumber were attributed to photoluminescence from Sm³⁺ ions. The formation of defect complexes play leading roles in the removal of prevent the grain growth, and photoluminescence quenching. (Ba_1−xSm_x)(Ti_{1−(x−0.01)}Cr_x−0.01)O₃ (BSTC1) ceramics with amphoteric Sm³⁺ ions exhibit a regular diffuse phase transition behavior, rapid T_m-shifting rate of −24.3 °C/at% (Sm/Cr), higher lower tan δ and x = 0.04 and 0.05 met the EIA Y5V specification.