The structural characteristics and microwave dielectric properties of Ti4+ doped CaMgSi2O6 ceramics

Abstract

The effect of Ti substitution on microwave dielectric properties and structural characteristics of CaMgSi2O6 ceramics synthesized via solid-state reaction method was investigated by XRD, XPS, Raman spectroscopy, SEM, EDS, Rietveld refinement, P–V-L theory and bond valence theory. XRD patterns indicated that CaTiO3 was gradually formed with the increase in Ti content. The permittivity was closely related to ionic polarizability, which was confirmed by Raman shifts. Quality factor (Q × f) and temperature coefficient of resonant frequency (τf) were considerably affected by lattice stability. Moreover, lattice energy and cation ordering of CaMgSi2O6 influenced Q × f, while cation bond valence affected the τf value. Improved microwave dielectric properties were achieved with high lattice energy and appropriate bond valence for well-densified CaMgSi1.95Ti0.05O6 ceramics with specific values of Q × f = 80774 GHz (±2578 GHz; @13.47 GHz, tan δ = 1.67 × 10−4), εr = 7.94 (±0.208), and τf = −58.56 ppm/°C (±2.65 ppm/°C) with high relative density (ρr = 96.9%).