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

The Ca 0.245 Li 0.325 Nd 0.395 Ti 1− x Sn x O 3 ( x  = 0–0.12) ceramics were prepared by the traditional solid-state reaction method. The effects of Sn 4+ substitution for Ti 4+ on the phase composition, microstructure, and microwave dielectric properties of Ca 0.245 Li 0.325 Nd 0.395 Ti 1− x Sn x O 3 (CLNTS x ) 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 SnO 2 was observed with x  > 0.09. The SEM micrographs indicated that the proper Sn 4+ substitution for Ti 4+ promoted the grain growth and homogenization. The analysis results of Raman spectroscopy revealed the correlation between vibration modes and microwave dielectric properties of CLNTS x ceramics with different Sn 4+ 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  ×  f 0 value. The excellent microwave dielectric properties with ε r  = 98, Q  ×  f 0  = 3320 GHz, and τ f  = 2.6 ppm/°C were obtained in the ceramics with x  = 0.09 sintered at 1350 °C for 4 h.