Hole-pinned defect-dipoles induced colossal permittivity in Bi doped SrTiO3 ceramics with Sr deficiency

摘要

Bi doped SrTiO3 ceramics with Sr deficiency,i.e.Sr1-1.5xBixTiO3(x=0,0.01,0.05,0.1),were prepared via conventional solid-state reaction route.A colossal permittivity(CP)over 104 with low dielectric loss less than 0.05wasobtained in x=0.05 Sr1-1.5xBixTiO3 ceramics.In addition,the dielectric constant is maintained at a value greater than 104 in the range of 102-105 Hz and almost frequency independent.Phase structure analysis and density functional theory calculations suggest that the Bi·Sr-V"Sr-Bi·Sr defect complex with hole-pinned defect-dipoles maybe responsible for the high-performance CP properties.This work gives a new way to achieve high performance CP materials in ABO3 perovskite ceramics.