Structural and microwave dielectric properties of high-permittivity Ca0.245Li0.325Nd0.395Ti1-xSnxO3 ceramics

The Ca0.245Li0.325Nd0.395Ti1-xSnxO3 (x = 0-0.12) ceramics were prepared by the traditional solid-state reaction method. The effects of Sn4+ substitution for Ti4+ on the phase composition, microstructure, and microwave dielectric properties of Ca0.245Li0.325Nd0.395Ti1-xSnxO3 (CLNTSx) were investigated in this work. The X-ray diffraction results showed that the ceramics had a single orthorhombic perovskite structure when x = 0-0.09. However, a secondary phase SnO2 was observed with x > 0.09. The SEM micrographs indicated that the proper Sn4+ substitution for Ti4+ promoted the grain growth and homogenization. The analysis results of Raman spectroscopy revealed the correlation between vibration modes and microwave dielectric properties of CLNTSx ceramics with different Sn4+ contents. The degree of cation order was related to the full width at half maximum (FWHM) of the Raman spectrum, and a lower FWHM value indicates higher cationic order and Q x f(0) value. The excellent microwave dielectric properties with epsilon(r) = 98, Q x f(0) = 3320 GHz, and tau(f) = 2.6 ppm/degrees C were obtained in the ceramics with x = 0.09 sintered at 1350 degrees C for 4 h.

Automated summary

The Ca0.245Li0.325Nd0.395Ti1-xSnxO3 (x = 0-0.12) ceramics were prepared and the effects of Sn4+ substitution for Ti4+ on their properties were studied. X-ray diffraction showed a single orthorhombic perovskite phase for x = 0-0.09, but a secondary phase SnO2 appeared with x > 0.09. Proper Sn4+ substitution promoted grain growth and homogenization. Raman spectroscopy revealed the correlation between vibration modes and microwave dielectric properties. Ceramics with x = 0.09 sintered at 1350℃ for 4 h exhibited excellent microwave dielectric properties, with epsilon(r) = 98, Q x f(0) = 3320 GHz, and tau(f) = 2.6 ppm/℃.