A new low-loss SrLaMgTaO₆ microwave dielectric ceramic with cubic structure

This study delves into the microwave dielectric properties of SrLaMgTaO₆ ceramics synthesized via traditional solid-state methods. Precise lattice parameters observed at the optimal temperature were as follows: a = b = c = 7.97327 Å, with a corresponding unit volume of V = 506.884775 ų. Utilizing X-ray diffraction (XRD) patterns and detailed Rietveld refinement analysis at various temperatures revealed that SrLaMgTaO₆ ceramics possess a cubic structure, specifically within the Fm-3 m (225) space group. The structure of ceramic particles was further studied by scanning electron microscopy ( SEM), and it was found that the optimum relative density was 95.7%. Additionally, within SrLaMgTaO₆ ceramic samples, the study explored the relationship between relative density, porosity, filler fraction, and microwave performance. A significant finding was the impact of the Ta–O bond valence (V_Ta–O) on the frequency temperature coefficient. At 1480 °C, SrLaMgTaO₆ ceramics demonstrated superior performance metrics: a dielectric constant (ε_r) of 21.68, a quality factor (Q × f) of 16,739 GHz (f = 8.74 GHz), and a frequency temperature coefficient (τ_f) of -79.1 ppm/°C. The findings highlight the material’s potential as a robust dielectric in microwave applications.