Impact of Lanthanoid Substitution on the Structural and Physical Properties of the Infinite Layer Iron Oxide
Impact of Lanthanoid Substitution on the Structural and Physical Properties of the Infinite Layer Iron Oxide
复制标题
镧系元素取代对无限层氧化铁结构和物理性能的影响
DOI：
10.1021/acs.inorgchem.6b02513
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发表时间：
2016
影响因子：
4.6
通讯作者：
H.;
中科院分区：
文献类型：
--
作者：
Yamamoto;T.; Ohokubo;H.; Tassel;C.; Hayashi;N.; Kawasaki;S.; Okada;T.; Yagi;T.; Hester;J.; Avdeev;M.; Kobayashi;Y.; Kageyama;H.;
通过常压和高压下的 X 射线衍射 (XRD)、中子衍射和 57Fe 穆斯堡尔谱研究了镧系元素 (Ln = Nd、Sm、Ho) 取代对无限层氧化铁 SrFeO2 的结构和物理性质的影响。使用 CaH2 通过拓扑化学还原合成了高达 ∼30% 的 Ln 取代 Sr 的样品。虽然较小的 Ln3+ 离子的引入如预期减少了轴，但我们发现轴和体积出现了异常的膨胀。 Rietveld 改进和对分布函数分析揭示了 FeO2 层之间氧原子的结合，其电荷补偿成分为 (Sr1–xLnx)FeO2+x/2，这解释了 FeO2 层电子掺杂失败的原因。掺入的部分顶端氧或锥体配位会引起 FeO2 片的不相干屈曲，导致尼尔温度显着降低。 (Sr0.75Ho0.25)FeO2.125 的高压 XRD 实验表明，与 SrFeO2 相比，中间自旋态可能更稳定，揭示了面内 Fe-O 距离对压力诱导转变的一定贡献。
The effect of lanthanoid (Ln = Nd, Sm, Ho) substitution on the structural and physical properties of the infinite-layer iron oxide SrFeO2was investigated by X-ray diffraction (XRD) at ambient and high pressure, neutron diffraction, and57Fe Mössbauer spectroscopy. Ln for Sr substituted samples up to ∼30% were synthesized by topochemical reduction using CaH2. While the introduction of the smaller Ln3+ion reduces theaaxis as expected, we found an unusual expansion of thecaxis as well as the volume. Rietveld refinements along with pair distribution function analysis revealed the incorporation of oxygen atoms between FeO2layers with a charge-compensated composition of (Sr1–xLnx)FeO2+x/2, which accounts for the failed electron doping to the FeO2layer. The incorporated partial apical oxygen or the pyramidal coordination induces incoherent buckling of the FeO2sheet, leading to a significant reduction of the Néel temperature. High-pressure XRD experiments for (Sr0.75Ho0.25)FeO2.125suggest a possible stabilization of an intermediate spin state in comparison with SrFeO2, revealing a certain contribution of the in-plane Fe–O distance to the pressure-induced transition.