Crystal structure and ionic conductivity of novel rare earth niobates LnNbO4 (Ln = Nd, Sm, Eu, Gd) by substituting Nb with W
Crystal structure and ionic conductivity of novel rare earth niobates LnNbO4 (Ln = Nd, Sm, Eu, Gd) by substituting Nb with W
复制标题
W取代Nb的新型稀土铌酸盐LnNbO4 (Ln = Nd, Sm, Eu, Gd)的晶体结构和离子电导率
DOI：
10.1007/s11581-023-05037-4
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发表时间：
2023
期刊：
影响因子：
2.8
通讯作者：
Keitaro Tezuka
中科院分区：
文献类型：
--
作者：
Yue Jin Shan;Ryo Kawaguchi;Ryoji Akizawa;Keitaro Tezuka
采用固相反应法系统地合成了W取代的稀土铌酸盐（LnNb 1 − xWxO 4 +δ（Ln= Nd，Sm，Eu，Gd））。室温下的X射线粉末衍射表明，随着W取代量的增加，未取代样品的单斜相结构逐渐转变为四斜相结构。x ≥ 0.3的样品的晶体结构可以很好地细化（拟合优度指标S ≤ 1.5）为四斜白钨矿结构。W取代提高了四种稀土氧化物的离子电导率，其最佳取代量x均为0.2。无论稀土离子的类型、温度和W的取代量如何，取代样品的电导率的激活能几乎是恒定的。
W-substituted rare-earth niobates (LnNb1 −xWxO4 +δ(Ln= Nd, Sm, Eu, Gd)) have been systematically synthesized by a solid-state reaction method. Powder X-ray diffraction at room temperature revealed that the monoclinic fergusonite phase structure of unsubstituted samples gradually changes to a tetragonal scheelite phase structure with increasing W substitution. The crystal structures of the samples withx≥ 0.3 can be refined well (goodness-of-fit indicatorS≤ 1.5) as the tetragonal scheelite structure. The W substitution improves the ionic conductivities of the four rare-earth niobates, and all of their optimum W substitution amount (x) are 0.2. The activation energy of the conductivity for the substituted samples is almost constant regardless of the type of rare-earth ion, the temperature, and the W substitution amount.