Microwave dielectric properties of low firing (Na0.5Ln0.5)MoO4 (Ln=Nd and Ce) ceramics

Abstract A new series of sheelite structured (Na 0.5 Ln 0.5 )MoO 4 (Ln=Nd and Ce) ceramics was prepared by using the traditional solid state reaction method. The (Na 0.5 Nd 0.5 )MoO 4 ceramic could be well densified at 760 °C with excellent microwave dielectric properties (a permittivity of ~10.5, a quality factor Q × f of ~19,605 GHz ( f =9.15 GHz) and a temperature coefficient of frequency of (TCF or τ f )~ −49 ppm/ o C). Meanwhile, the (Na 0.5 Ce 0.5 )MoO 4 ceramic sintered at 780 °C possessed the best microwave dielectric properties with a permittivity of ~11.2, a Q × f value of 19,365 GHz ( f =8.98 GHz) and TCF of approximately −44 ppm/ °C. The (Na 0.5 Nd 0.5 )MoO 4 ceramic was found to be chemically compatible with Ag electrode at its sintering temperature. It is a promising microwave dielectric material for low-temperature co-fired ceramic technology (LTCC). However, the (Na 0.5 Ce 0.5 )MoO 4 ceramic was found to react with Ag after co-firing at 780 °C for 2 h and this limited its application in LTCC technology.