Substituting La3+ with Sr2+ to improve microwave dielectric properties of La(Mg0.5Sn0.5)O3 ceramics

The microwave dielectric properties of La(1−2x/3)Srx(Mg0.5Sn0.5)O3 ceramics were examined with a view to their exploitation for mobile communication. The La(1−2x/3)Srx(Mg0.5Sn0.5)O3 ceramics were prepared by the conventional solid-state method with various sintering temperatures. The X-ray diffraction peaks of the La(1−2x/3)Srx(Mg0.5Sn0.5)O3 ceramics shifted to lower angles as x increased from 0 to 0.05. The X-ray diffraction patterns of the La2.98/3Sr0.01(Mg0.5Sn0.5)O3 ceramics revealed no significant variation of phase with sintering temperatures. A maximum density of 6.56 g/cm3 was obtained for La2.98/3Sr0.01(Mg0.5Sn0.5)O3 ceramic, sintered at 1550 °C for 4 h. A dielectric constant (ɛr) of 20.0 and a product of quality factor and resonant frequency (Q × f) of 57,100 GHz and a temperature coefficient of resonant frequency (τf) of −77 ppm/°C were obtained for La2.98/3Sr0.01(Mg0.5Sn0.5)O3 ceramics that were sintered at 1550 °C for 4 h.