Microwave dielectric properties of A-site modified Ba(Co0.7Zn0.3)1/3Nb2/3O3 by La3+

The sintering behavior, ordering state, and microwave dielectric properties of Ba1-xLa2x/3(Zn0.3Co0.7)(1/3)Nb2/3O3 Ceramics (0 <= x <= 0.06) were investigated in this paper. The X-ray diffraction (XRD) results show that all samples exhibit a single perovskite phase except for the sample with x >= 0.03. The sinterability is slightly improved by La doping. The long range order (LRO) degree on B-site is greatly increased with the increase of x value up to x=0.015 and then slightly decreased with the further increase of x due to the increasing amount of second phases. The dielectric constant at microwave frequency decreases slightly with the increase of x when x < 0.015 and increases slightly with further increasing x for the samples sintered at 1375 degrees C/10 h. The Q x f value increases with x up to x=0.015 and then decreases with further increase of x, which is consistent with the variation trend of LRO degree. The tau(f) value decreases slightly with the increase of x up to 0.006, then increases greatly with the further increase of x. An optimized dielectric properties of epsilon(r)=34, Q x f = 63 159, GHz and tau(f)=5.21 ppm/degrees C were obtained for the x=0.01 sample sintered at 1425 degrees C/10 h.