Q factor enhancement in Nd2Zr3(MoO4)9 microwave ceramics via B-site (Bi0.5Ta0.5)4 + substitution and low-temperature sintering

Low-temperature sintered microwave dielectric ceramics are gaining increasing attention for next-generation wireless communication systems, particularly within the 6 G frequency range. However, materials that simultaneously exhibit ultra-low dielectric loss and low sintering temperatures remain scarce. In this study, Nd 2 [Zr 1-X (Bi 0.5 Ta 0.5 ) X ] 3 (MoO 4 ) 9 ceramics were prepared via a conventional solid-state reaction method and exhibited a single-phase structure with a trigonal symmetry (space group R 3 ¯ C, No. 167). The optimal sample at x = 0.11 sintered at 750 ℃ showed excellent performance: ε r = 11.4, Q×f = 186,300 ± 8900 GHz, and τ f = –42.9 ppm/℃. The elevated Q×f value is chiefly ascribed to increased lattice energy, with its variation more plausibly arising from intrinsic effects within the material. The dielectric constant (εᵣ), analyzed using the Clausius–Mosotti equation, was predominantly influenced by ionic polarizability. According to P–V–L theory, the effective bond strength f iNd–O played a major role in determining εᵣ, while τ f was governed by the bond energy and thermal expansion behavior of Mo–O bonds. Raman spectroscopy further confirmed the structure–property relationships. These results suggest that B-site substitution with (Bi 0.5 Ta 0.5 ) 4+ not only promotes densification and increases lattice energy, but also maintains thermal stability, thereby enhancing Q×f without compromising τ f . This system offers strong potential for integration into future microwave dielectric components.