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 Ba_{1− x} La_{2 x /3}(Zn_0.3Co_0.7)_1/3Nb_2/3O₃ 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°C/10 h. The Q × 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 τ_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 ɛ _r =34, Q × f =63 159, GHz and τ_f=5.21 ppm/°C were obtained for the x =0.01 sample sintered at 1425°C/10 h.