Structure related dielectric properties of phosphorus enriched LiMgPO4 microwave dielectric ceramics

In this study, phosphorus enriched LiMgP 1+ x O 4 (0.00 ≤ x  ≤ 0.04) ceramics were synthesized via the solid-state reaction route. The crystal and phase structure patterns were analyzed by the Rietveld refinement and Raman spectroscopy. The dielectric properties were obtained at both microwave and terahertz frequencies. Optimal microwave dielectric performance was obtained in LiMgP 1.01 O 4 , sintered at 875 °C for 4 h: ε r  = 6.964, Q × f  = 82,057 GHz, and τ f  = −27.1 ppm/°C (at 15.361 GHz). Compared with the pure LiMgPO 4 ceramics sintered at 950 °C ( Q × f  = 79,100 GHz and τ f  = −55 ppm/°C), an appropriate amount of excessive P 5+ reduced the sintering temperature while improving the Q × f value and the thermal stability effectively. Within the terahertz frequency range of 0.2–1.2 THz, the ε r values were decreased to 5.40–6.65 while the tan δ values were ranged from 0.0039 to 0.1228. All experimental results suggested that the LiMgP 1+ x O 4 ceramics are promising for both microwave and terahertz frequency applications.