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

The crystal structure and dielectric properties of Ti 4+ -substituted CaSnSiO 5 ceramic were investigated. Ti 4+ entirely substituted Sn 4+ of CaSnSiO 5 , and the solid solutions were formed at Ca(Sn 1- x Ti x )SiO 5 (0 ≤ x ≤ 1.0) ceramics. The evolutions of crystal structure were analysed through Rietveld refinement and transmission electron microscopy , and the phase transition from A 2/ a to P 2 1 / a space groups at Ca(Sn 1- x Ti x )SiO 5 (0.9 ≤ x ≤ 1.0) ceramics was clarified. The change in dielectric properties was related to the structural evolution of Ca(Sn 1- x Ti x )SiO 5 (0 ≤ x ≤ 1.0). The τ f values of Ca(Sn 1- x Ti x )SiO 5 (0 ≤ x ≤ 0.4) ceramics initially decreased to +49.8 ppm/°C and then increased to +98.3 ppm/°C because of Sn/TiO 6 octahedral distortion. The temperature coefficient of capacitance and ε r anomaly peak were controlled by Ti 4+ substitution for Sn 4+ at Ca(Sn 1- x Ti x )SiO 5 (0.4 ≤ x ≤ 1.0) ceramics. The results provided a way to control the τ f value of microwave dielectric ceramics .