Effect of hydrogen on sublattice magnetization of Laves‐phase rare earth iron compounds
Effect of hydrogen on sublattice magnetization of Laves‐phase rare earth iron compounds
复制标题
氢对Laves相稀土铁化合物亚晶格磁化强度的影响
DOI：
10.1063/1.327139
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发表时间：
1979
影响因子：
3.2
通讯作者：
W. Wallace
中科院分区：
文献类型：
--
作者：
G. Fish;J. Rhyne;S. Sankar;W. Wallace
我们用弹性中子散射研究了氢化对R=Ho和Er的Laves相化合物RFe2亚晶格磁化强度的影响。加入氢或氢后，形成了RFe2D3.5左右的稳定相。纯化合物RFe2是亚铁磁性的，其R矩等于ErFe2D3.5的自由离子温度和∼1.6ErFe2的Fe磁矩。氢化物和氢化物的体居里温度T_c明显低于相应的RFe_2值(例如，ErFe_2D_(3.5)的440K和ErFe_2的574K)。氢化物的10K-R矩也显著减小(4.4和5.2μB比RFe2中Er和Ho的9和10μB)，并随着温度的升高而稳步下降，在Er的情况下达到零。Fe2D3.5和HoFe2D3.5的磁矩分别为1.6μB和1.9μB，在略低于T_c时，Fe磁矩随温度变化不大。这些结果表明，氢化物中与R原子有关的交换作用明显减弱。由于H的随机占据和R的弱交换耦合引起的局域各向异性场的扭曲，产生了R矩的“扇形”，这减小了在中子实验中测量的空间平均矩。
We have used elastic neutron scattering to examine the effect of hydriding on the sublattice magnetization of the Laves‐phase compounds RFe2 for R=Ho and Er. On addition of hydrogen or deuterium a stable phase of composition about RFe2D3.5 is formed. The pure compounds RFe2 are ferrimagnetic, with the R moment equal to the free ion value and Fe moment of ∼1.6 μB. The bulk Curie temperatures Tc of the hydrides and deuterides are considerably lower than the corresponding RFe2 values (e.g., 440 K for ErFe2D3.5 versus 574 K for ErFe2). The 10 K R moment is also significantly reduced in the deuterides (4.4 and 5.2 μB versus 9 and 10 μB for Er and Ho in RFe2) and drops steadily with increased temperature, reaching zero below Tc in the case of Er. The Fe moment remains nearly constant with temperature until just below Tc where it drops rapidly to zero; in ErFe2D3.5 and HoFe2D3.5 its magnitude is 1.6 μB, and 1.9 μB, respectively. These results indicate that the exchange interactions involving the R atoms are markedly weakened in the hydrides. The distortion of the local anisotropy field due to random site occupancy of H and the weak exchange coupling of R produces a ’’fanning’’ of the R moment which reduces the spatially averaged moment measured in the neutron experiment.