Contrasting microwave dielectric properties of zircon-structured AEuV2O8 (A = Bi, La) ceramics

Two zircon-structured ceramics AEuV 2 O 8 (A = Bi, La) were prepared with optimal sintering temperatures of 900 °C and 1375 °C, respectively. They exhibited sharp contrast performances with medium ε r ∼ 28.7 ± 0.1, Q × f ∼ 14,000 ± 300 GHz, and large positive τ f ∼ 75.7 ± 2.0 ppm/°C for BiEuV 2 O 8 , whereas low ε r ∼ 10.4 ± 0.1 Q × f ∼ 25,100 ± 300 GHz, and negative τ f ∼ − 40.7 ± 2.0 ppm/°C for LaEuV 2 O 8 . The rattling effect at the A-site was more dominant in determining microwave dielectric properties than that of compressed V 5+ at the B-site. It resulted in the higher ε r , lower Q × f and τ ε , and larger τ f of BiEuV 2 O 8 than those of LaEuV 2 O 8 . Besides, their Q × f was related with the relative density, bond valence and FWHM of the B 1 g Raman mode.