Abstract Ca9–xBaxBi(VO4)7 (0 ≤ x ≤ 1.5) solid solutions with the β-Ca3(PO4)2-type structure were prepared by a solid-state method. Powder X-ray diffraction study of 0 ≤ x ≤ 0.7 showed that Bi3+ and Ba2+ cations were completely incorporated into the β-TCP-type host framework up to x = 0.7. Ca9-xBaxBi(VO4)7 (x = 0.25, 0.5) structures were refined by the Rietveld method using powder synchrotron X-ray diffraction data. DSC, SHG and dielectric properties measurements of Ca9-xBaxBi(VO4) (x = 0, 0.25, 0.5) revealed two reversible first-order phase transitions (PT1 and PT2). Increase of Ba2+ content in Ca9-xBaxBi(VO4)7 leads to lowering PT1 and PT2 phase transitions temperatures due to the increase of cell volume and the structure looseness. Nonlinear optical activity of Ca9–xBaxBi(VO4)7 reaches its maximum response at x = 0.5. The amount of (M1–(M3)–M2) dipoles in Ca9–xBaxBi(VO4)7 (0

中文翻译：

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钡对β-Ca3(PO4)2型Ca9Bi(VO4)7结构和性质的影响

摘要 采用固相法制备了β-Ca3(PO4)2型结构的Ca9-xBaxBi(VO4)7 (0 ≤ x ≤ 1.5)固溶体。0 ≤ x ≤ 0.7 的粉末 X 射线衍射研究表明 Bi3+ 和 Ba2+ 阳离子完全结合到 β-TCP 型主体框架中，直至 x = 0.7。Ca9-xBaxBi(VO4)7 (x = 0.25, 0.5) 结构通过 Rietveld 方法使用粉末同步加速器 X 射线衍射数据进行细化。Ca9-xBaxBi(VO4) (x = 0, 0.25, 0.5) 的 DSC、SHG 和介电特性测量显示两个可逆的一阶相变（PT1 和 PT2）。Ca9-xBaxBi(VO4)7 中 Ba2+ 含量的增加导致 PT1 和 PT2 相变温度降低，这是由于细胞体积和结构松散的增加。Ca9–xBaxBi(VO4)7 的非线性光学活性在 x = 0.5 时达到其最大响应。