Synthesis And Microwave Dielectric Properties Of Cu-Doped Znal2o4

Spinel materials of composition Zn1-xCuxAl2O4 (ZCA, x = 0-0.015) were prepared via the conventional solid-state route. The lattice structure, microstructure, and microwave dielectric properties were investigated as a function of Cu content. Cu doping was found to improve the sinterability and, meanwhile, significantly increase the quality factor (Q x f(0)), which is due to the Cu-O bond is stronger than Zn-O bond, and inhibit the oxygen vacancy considered to be responsible for the enhanced Q x f(0) value of ZCA materials. The best microwave dielectric properties were obtained in Zn0.99Cu0.01Al2O4 with epsilon(r) = 8.69, Q x f(0) = 69,300 GHz and (f) = -58.3 ppm/degrees C, which was sintered at 1520 degrees C for 3 h in air.