Structure and modified giant dielectric response in CaCu 3(Ti 1− xSn x) 4O 12 ceramics

Abstract

The influence of Sn-substitution on structure, dielectric properties and conductivity of CaCu 3Ti 4O 12 ceramics was investigated. Single-phase structures with space group Im 3 ¯ were obtained up to x = 0.1 in CaCu 3(Ti 1− x Sn x ) 4O 12. The giant dielectric constant step became lower with Sn-substitution by depressing both the low and high temperature dielectric relaxations. The room temperature dielectric constant and dielectric loss of CaCu 3(Ti 1− x Sn x ) 4O 12 decreased with increasing Sn-substitution. The dielectric constant decreased from 79,846 to 31,324 when x changed from 0 to 0.1, while and the dielectric loss was suppressed from 0.083 to 0.062 (at 10 kHz). XPS analysis results confirmed the obvious decrease of Ti 3+/Ti 4+ and Cu +/Cu 2+ ratio, and the decreased giant dielectric response was primarily attributed to the modification of the mixed-valent structure of Ti 3+/Ti 4+ and Cu +/Cu 2+.