Tuning microwave dielectric properties of low-temperature sintered Ca1-x(Li0.5Eu0.5)xMoO4 (0.1 ≤ x ≤ 0.5) ceramics by the strong rattling effect of Li

In this work, a series of Ca1-x(Li0.5Eu0.5)xMoO4 (0.1 <= x <= 0.5) ceramics was obtained by the conventional solidstate reaction method within the sintering temperature of 750-875 degrees C. XRD patterns combined with Rietveld refinement results show that all the Ca1-x(Li0.5Eu0.5)xMoO4 ceramics are crystallized in a tetragonal scheelite structure. Bond valence analysis demonstrates that Li+ exhibits a strong rattling effect, resulting in an abnormal increase in epsilon r from 11.5 to 15.1. An intriguing phenomenon is observed in the variation of tau & fnof; (-14.40 ppm/degrees C sharply increases to +128.42 ppm/degrees C), which may be due to the decreased tau alpha m values caused by the rattling Li+ cations. The excellent microwave dielectric properties (epsilon r = 11.9, Qxf = 42,500 GHz, and tau f = +1.76 ppm/degrees C) of the Ca0.85(Li0.5Eu0.5)0.15MoO4 ceramic exhibit good chemical compatibility with Ag powders, indicating that it may be a promising candidate for applications used in low-temperature cofired ceramic technology.