Enhancement of microwave dielectric properties via the synergy of moderate lattice distortion and delayed diffusion

Abstract The microwave dielectric properties of CaMoO 4 were significantly enhanced by partial strontium substitution using a solid‐state synthesis method. Sr substitution effectively reduced the sintering temperature. The lattice mismatch‐induced local stress fields and distortions may extend to the macroscopic scale, ultimately resulting in residual strain. The temperature coefficient of the resonant frequency can be enhanced by moderate strain fields and lattice distortions. Ionic transport was suppressed, and dielectric loss was further reduced owing to the mitigation of oxygen vacancies, blockage of diffusion pathways, and the increase in the migration energy barrier induced by Sr incorporation. Ultimately, (Ca 0.5 Sr 0.5 )MoO 4 ceramics sintered at 950°C exhibited excellent dielectric performance ( ε r = 10.15, Q × f = 99 928 GHz, τ f = ‒8.55 ppm/°C).