Electronic and magnetic properties of NiMn1−xHoxSb compounds

We study the effects of holmium doping in the half-Heusler compound NiMnSb. Band structure calculations show that the half-metallic properties are completely conserved if holmium atoms substitute the manganese ones. The antiparallel coupling of Ho and transition metal magnetic moments was found to be more favorable. The magnetization measurements are in agreement with the results of the structural and XPS analysis and confirm that the holmium atoms occupy lattice sites. There is a very good agreement between the experimental magnetic moments determined at 4.2 K and the calculated ones in the case of antiferromagnetic coupling between the Ho and transition metal magnetic moments.