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

Abstract

A new series of sheelite structured (Na0.5Ln0.5)MoO4 (Ln=Nd and Ce) ceramics was prepared by using the traditional solid state reaction method. The (Na0.5Nd0.5)MoO4 ceramic could be well densified at 760°C with excellent microwave dielectric properties (a permittivity of ~10.5, a quality factor Q×f of ~19,605GHz (f=9.15GHz) and a temperature coefficient of frequency of (TCF or τf)~ −49ppm/oC). Meanwhile, the (Na0.5Ce0.5)MoO4 ceramic sintered at 780°C possessed the best microwave dielectric properties with a permittivity of ~11.2, a Q×f value of 19,365GHz (f=8.98GHz) and TCF of approximately −44ppm/°C. The (Na0.5Nd0.5)MoO4 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 (Na0.5Ce0.5)MoO4 ceramic was found to react with Ag after co-firing at 780°C for 2h and this limited its application in LTCC technology.