Department of Physics, Loughborough University, LE11 3TU, UK. Institut Laue Langevin, BP 156, 38042 Grenoble, France.
J Phys Condens Matter. 2010 May 26;22(20):206004. doi: 10.1088/0953-8984/22/20/206004. Epub 2010 Apr 26.
Polarized neutron diffraction has been used to study the magnetization distribution in two isostructural inter-metallic compounds NiMnSb and PdMnSb. Band structure calculations have predicted that whereas the former should be a half metallic ferromagnet the latter should not. Measurements made at 5 K on different crystals show that disorder can occur between the A (Mn) and B (Sb) sites in both alloys and in the case of NiMnSb, by partial occupation of the void D sites by Ni. In all the crystals most of the moment was found on the Mn atoms in the A sites; in NiMnSb it is due to spin only but in PdMnSb there is evidence for a significant orbital contribution (g = 2.22). The magnitudes of the moments associated with each atom are in fair agreement with the theoretical values; however, the distribution of magnetization around the Mn atoms is found to have nearly spherical symmetry (40% e(g)) rather than the 50% e(g) character expected from the band structure.
利用偏振中子衍射研究了两种同构金属间化合物 NiMnSb 和 PdMnSb 中的磁化分布。能带结构计算预测前者应为半金属铁磁体，而后者不应如此。在不同晶体上于 5 K 下进行的测量表明，两种合金中的 A（Mn）和 B（Sb）位之间可能发生无序，并且 Ni 部分占据空 D 位。在所有晶体中，大部分磁矩都位于 A 位的 Mn 原子上；在 NiMnSb 中，这归因于自旋，但在 PdMnSb 中，存在显著的轨道贡献（g = 2.22）的证据。与每个原子相关的磁矩的大小与理论值相当吻合；然而，发现 Mn 原子周围的磁化分布具有近球对称（40% e(g)）而不是从能带结构预期的 50% e(g)特征。
