Structure, bond chemistry and enhanced microwave dielectric properties of La2−xYxMo2O9 ceramics with low sintering temperature

Abstract

Low-temperature sintered La2−xYxMo2O9 ceramics (x = 0–0.12) were synthesized by solid-state method. XRD analysis confirmed pure La2Mo2O9 with a cubic structure (space group P 21 3). Sintering at 925 °C resulted in La2Mo2O9 ceramic with favorable microwave dielectric properties: εr = 17.8, Q × f = 24300 GHz, τf = −35.1 ppm/°C. Notably, adding Y3+ greatly improved Q × f and τf. Sintering La1.88Y0.12Mo2O9 at 900 °C significantly enhanced microwave dielectric properties: εr = 17.4, Q × f = 34100 GHz, τf = −5.5 ppm/°C. εr was primarily influenced by ionic polarizability, while Q × f correlated positively with packing fraction. Analysis based on P-V-L theory showed that increased ionicity, lattice energy, and bond energy led to higher εr, Q × f, and τf values. Raman spectroscopy revealed that most observed peaks were associated with Mo-O bond vibrations. These findings highlight La2−xYxMo2O9 ceramics as promising candidates for LTCC materials.