Correlation between crystal structure and dielectric characteristics of Ti4+ substituted CaSnSiO5 ceramics

Abstract The crystal structure and dielectric properties of Ti4+-substituted CaSnSiO5 ceramic were investigated. Ti4+ entirely substituted Sn4+ of CaSnSiO5, and the solid solutions were formed at Ca(Sn1-xTix)SiO5 (0 ≤ x ≤ 1.0) ceramics. The evolutions of crystal structure were analysed through Rietveld refinement and transmission electron microscopy, and the phase transition from A2/a to P21/a space groups at Ca(Sn1-xTix)SiO5 (0.9 ≤ x ≤ 1.0) ceramics was clarified. The change in dielectric properties was related to the structural evolution of Ca(Sn1-xTix)SiO5 (0 ≤ x ≤ 1.0). The τf values of Ca(Sn1-xTix)SiO5 (0 ≤ x ≤ 0.4) ceramics initially decreased to +49.8 ppm/°C and then increased to +98.3 ppm/°C because of Sn/TiO6 octahedral distortion. The temperature coefficient of capacitance and er anomaly peak were controlled by Ti4+ substitution for Sn4+ at Ca(Sn1-xTix)SiO5 (0.4 ≤ x ≤ 1.0) ceramics. The results provided a way to control the τf value of microwave dielectric ceramics.