Rare Earth Ion-Doped Y2.95R0.05MgAl3SiO12 (R = Yb, Y, Dy, Eu, Sm) Garnet-Type Microwave Ceramics for 5G Application

In this work, Y2.95R0.05MgAl3SiO12 (R = Yb, Y, Dy, Eu, Sm) microwave single-phase dielectric ceramics were successfully prepared via a conventional ceramic sintering technology by doping a series of rare earth elements (Yb, Y, Dy, Eu, Sm) with different ionic radii for the first time. The effects of A-sites occupied by rare earth elements on the microwave dielectric properties of Y2.95R0.05MgAl3SiO12 were studied using crystal structure refinement, a scanning electron microscope (SEM), bond valence theory, P-V-L theory, and infrared reflection spectroscopy. It was found that the ionicity of the Y-O bond, the lattice energy, the bond energy, and the bond valance of the Al-(Tet)-O bond had important effects on the microwave dielectric properties. Particularly, the optimum microwave dielectric properties, epsilon(r) = 9.68, Q x f = 68,866 GHz, and tau(f) = -35.8 ppm/degrees C, were obtained for Y2.95Dy0.05MgAl3SiO12 when sintered at 1575 degrees C for 6 h, displaying its potential for 5G communication.