Crystal structure and dielectric properties of Mo-modified BaZnP2O7 ceramics in microwave and terahertz frequencies

In this study, BaZnP 2- x Mo x O 7+ x /2 (BZPM x , 0 ≤ x  ≤ 0.03) ceramics were successfully sintered at low temperatures via the solid-state reaction. Rietveld refinement, surface morphology characterization, and Raman spectroscopy were employed to clarify the effects of Mo 6 + substitution on the crystallology and microstructure evolution of the BZPM x ceramics. Dielectric properties were evaluated in both microwave and terahertz frequencies. Optimal microwave dielectric properties were obtained at x  = 0.02, sintered at 825 ℃ for 4 h: ε r = 8.073(±0.012), Q×f = 73,172(±1187) GHz (@13.687 GHz), and τ f = -31.9(±1.6) ppm/℃. Compared with the pure BaZnP 2 O 7 ceramic sintered at 875 ℃ ( Q×f = 47,984 GHz and τ f = −40.2 ppm/℃), the incorporation of Mo 6+ could reduce the dielectric loss and improve the thermal stability while reducing the sintering temperature simultaneously. In the terahertz frequency range of 0.2 ∼ 1.2 THz, the ε r values decreased to 5.35 ∼ 7.24 while the tan δ values were within the range of 0.0105 ∼ 0.0319. All experimental results indicated that the BZPM x ceramics are promising for LTCC devices in both microwave and terahertz frequencies.