A structural analysis and some magnetic properties of the R2Fe17Hx series
A structural analysis and some magnetic properties of the R2Fe17Hx series
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R2Fe17Hx系列的结构分析和一些磁性能
DOI：
10.1016/0304-8853(94)90201-1
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发表时间：
1994
影响因子：
2.7
通讯作者：
P. L'héritier
中科院分区：
文献类型：
--
作者：
O. Isnard;S. Miraglia;J. Soubeyroux;D. Fruchart;P. L'héritier
通过R系列（除了R = Eu, Yb）对化合物sr2fe17hx进行了结构和磁性表征。轻稀土和重稀土合金的初始晶型分别为菱形（Th2Zn17-typeR-3m）和六边形（Th2Ni17-typeP63/mmc）。可以看出，加氢后基体合金的对称性仍保持不变。氢被发现可以容纳富含稀土的八面体和四面体位点。重稀土和轻稀土的最大吸氢量分别为3 ~ 5个氢原子/分子式单位。分析了氢化过程中电池的高度各向异性膨胀。提出了一种充氢方案。研究了加氢对astc等本征磁性参数和总磁化强度的影响。它与结构内Fe-Fe短距离的变化有关，并根据交换相互作用的变化进行了讨论。结果还表明，加氢改变了某些化合物的各向异性常数的热变化。
A structural and magnetic characterization of the compoundsR2Fe17Hxthrough the R series (except for R = Eu, Yb) is presented. The starting alloys crystallize with the rhombohedral (Th2Zn17-typeR-3m) or the hexagonal (Th2Ni17-typeP63/mmc) structure for the light and heavy rare earths, respectively. It is seen that the host alloy symmetry is retained upon hydrogenation. Hydrogen is found to accomodate rare earth-rich octahedral and tetrahedral sites. The maximum hydrogen uptake ranges from 3 to 5 hydrogen atoms per formula unit for the heavier and lighter rare earths, respectively. The highly anisotropic cell expansion upon hydrogenation is analyzed. A filling scheme for hydrogen is proposed. The effect of hydrogenation on intrinsic magnetic parameters such asTCand the total magnetization has been studied. It is correlated to the variation of short Fe-Fe distances within the structure and discussed in terms of variations of the exchange interaction. It is also shown that hydrogenation modifies the thermal variation of the anisotropy constants in some compounds.