The microwave dielectric properties of Ba[(Zn0.6Mg0.4)1/3Nb(2-x)/3Sbx/3]O3 perovskite ceramics

Ba[(Zn 0.6 Mg 0.4 ) 1/3 Nb (2- x )/3 Sb x /3 ]O 3 (BZMNS, x  = 0.15, 0.2, 0.25, 0.3, 0.35) ceramics were synthesized by the conventional solid-state reaction method. The crystal structure and microwave dielectric properties of the ceramics were investigated. X-ray diffraction (XRD) analysis revealed that the BZMNS ceramics exhibit a cubic perovskite structure. The crystal structures were refined, and no secondary phases were detected in all compositions. The doping of Sb 5+ hinders grain growth, and the average grain size first increases and then decreases with the increase of the x value. The dielectric constant shows a downward trend due to the influence of the ionic bond character of B-site ions and the B-site Rattling effect. The packing fraction is the main factor affecting the Q  ×  f value of BZMNS ceramics. As the x value increases, the temperature coefficient of the resonant frequency ( τ f ) gradually decreases. Ion polarizability dilution is the primary mechanism for regulating τ f of BZMNS ceramics. The BZMNS ceramics sintered at 1480 °C with x  = 0.3 exhibit optimal microwave dielectric properties ( ε  r = 31.44, Q  ×  f  = 62,273 GHz (at f₀  = 6.5 GHz), τ f  =  + 2.48 ppm·°C −1 ), indicating that this ceramic has good application prospects.