Abstract

Phosphate solid solutions based on the whitlockite family Ca_9 – xM_xDy(PO₄)₇ (M = Zn²⁺ or Mg²⁺) have been obtained. The samples have been investigated by a combination of the methods, such as X‑ray diffraction analysis, second optical harmonic generation, and luminescence spectroscopy. It is established that the unit-cell symmetry change (R3c → \(R\bar {3}c\)) in the solid-solution series with an increase in the degree of substitution Ca²⁺ → M²⁺; the concentration dependence is determined. Phase transitions of the ferro- and antiferroelectric types, as well as their temperature positions, have been determined by dielectric spectroscopy. The synthesized samples exhibit strong luminescence under 350-nm excitation with the resulting radiation in the white region in color coordinates.

中文翻译：

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磷酸盐Ca 9 – x M x Dy（PO 4）7（M = Zn 2+或Mg 2+）的结构特征

摘要

已获得了基于菱镁矿族Ca _{9 –  x} M _x Dy（PO ₄）₇（M = Zn ²⁺或Mg ²⁺）的磷酸盐固溶体。通过组合使用多种方法对样品进行了研究，例如X射线衍射分析，二次光学谐波生成和发光光谱法。可以确定，随着取代度Ca 2 ⁺ →M ²⁺的增加，固溶系列中的晶胞对称性变化（R 3 c → \（R \ bar {3} c \））。; 确定浓度依赖性。铁电和反铁电类型的相变及其温度位置已通过介电谱确定。合成的样品在350 nm激发下显示强发光，所得辐射在颜色坐标的白色区域中。