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通过固相反应法制备了MLnBO_4(M=Ba,Sr,Ca;Ln=La,Nd,Sm,Y;B=(Zn0.5Ti0.5),(Mg_(0.5)Ti_(0.5)))陶瓷粉末,使用X射线衍射仪(XRD)分析其相组成,并结合文献中B位为Ga和Al时的结果,探讨了MLnBO_4中K_2NiF_4型层状钙钛矿结构的稳定性。当M~(2+)和B~(3+)固定时,K_2NiF_4型结构的稳定性随钙钛矿层许容因子t偏离1程度的增加而降低;但当M~(2+)或B~(3+)改变时,两者之间并无直接联系。而考虑M~(2+)、Ln~(3+)、B~(3+)离子半径的对比时,则发现K_2NiF_4型结构均出现在以r(M~(2+))/r(Ln~(3+))=1.1、r(Ln~(3+))/r(B~(3+))=2为中心的一定范围内。因此,用M~(2+)、Ln~(3+)、B~(3+)离子半径的对比衡量MLnBO_4中K_2NiF_4型层状钙钛矿结构的稳定性远较用钙钛矿层的许容因子更可靠,这对于相关材料的设计和开发具有重要意义。
The ceramic powders of MLnBO_4 (M = Ba, Sr, Ca; Ln = La, Nd, Sm and Y; B = (Zn0.5Ti0.5) and (Mg_ (0.5) Ti_ (0.5) . The phase composition of the layered perovskite structure was investigated by X-ray diffraction (XRD). The stability of the layered perovskite structure of K_2NiF_4 in MLnBO_4 was discussed in combination with the results of the literature with Ga and Al at the B site. When M 2+ and B 3+ are fixed, the stability of K_2NiF_4 type structure decreases with the increase of the allowable factor t of perovskite layer 1; however, when M 2+ or B ~ (3+) change, there is no direct relationship between the two. However, when considering the comparison of the radii of M ~ (2 +), Ln ~ (3 +) and B ~ (3+) ions, it is found that the structures of K_2NiF_4 occur in the order of r ~ (3 +)) = 1.1, r (Ln ~ (3 +)) / r (B ~ (3 +)) = 2. Therefore, the stability of K 2 NiF 4 -type layered perovskite structure in MLnBO_4 is better than that of perovskite layer by the comparison of M 2 +, Ln 3+ and B 3+ ion radii Factors are more reliable, which is of great importance for the design and development of related materials.