Influence of Ca2+ substitution for Ba2+ on the crystal structure and microwave dielectric properties of Ba1−xCax(Mg1/3Ta2/3)O3 ceramics

Crystal structure dependence of the microstructure and microwave dielectric properties of (SrxCa1−x)(Zr0.95Ti0.05)O3 (0 ≤ x ≤ 1) perovskite ceramics

“…So the superlattice ordered structure driven by the change of regional microstructure is a short-range ordered structure, which is obviously different from the long-range ordered superlattice structure formed by the periodic ordered arrangement of B-site ions, such as Ba(Zn 1/3 Ta 2/3 )O 3 11,12 and Ba(Mg 1/3 Ta 2/3 )O 3 . 14,15 When the internal strain is too high or the ambient temperature rises, it is difficult to maintain the superlattice ordered structure, and the structure will be changed to a more stable cubic phase structure. 37 In order to explore the temperature dependence of crystal structure, the XRD of Sr(Zr 0.95 Ti 0.05 )O 3 measured at 150 °C and the Rietveld refinement are shown in Fig.…”

“…9 The representative microwave dielectric ceramics include (Zr 0.8 Sn 0.2 )TiO 4 ( ε r = 38, Q × f = 7000 GHz, τ f = 0 ppm °C −1 ), 10 Ba(Zn 1/3 Ta 2/3 )O 3 ( ε r = 28.2, Q × f = 121 600 GHz, τ f = 5.31 ppm °C −1 ), 11–13 and Ba(Mg 1/3 Ta 2/3 )O 3 ( ε r = 24, Q × f = 165 800 GHz, τ f = 0.12 ppm °C −1 ). 14,15 However, the low quality factor or a high raw material cost limit their application. Therefore, it is urgent to explore low-cost and high-performance microwave dielectric ceramics to meet the needs of 5G communication.…”

The latest process and challenges of microwave dielectric ceramics based on pseudo phase diagrams

“…Simulation is carried out for Ba(Zn 1/3 Ta 2/3 )O 3 for the design of linear metal taper [529]. Peng et al [530] reported that addition of La 2 O 3 into Ba(Mg 1/3 Ta 2/3 )O 3 , Ba 1-x Ca x (Mg 1/3 Ta 2/3 )O 3 , and Ba[Mg 1-x Zn x ] 1/3 Ta 2/3 O 3 led to the appearance of Ba 0.5 TaO 3 , and τ f value reached to near zero [531,532]. The optimal properties of Ba[Mg (1-x)/3 Sn x Ta 2(1-x)/3 ]O 3 exhibited as ε r ≈ 24.1, Q×f value ≈ 138,500 GHz, and τ f ≈ +0.2 ppm/ [533].…”