Ab initio calculations and synthesis of the off-stoichiometric half-Heusler phase Ni1-xMn1+xSb

作者：Ekholm M^*; Larsson P; Alling B; Helmersson U; Abrikosov I A

来源：Journal of Applied Physics, 2010, 108(9): 093712.

DOI：10.1063/1.3476282

We perform a combined theoretical and experimental study of the phase stability and magnetism of the off-stoichiometric Ni1-xMn1+xSb in the half-Heusler crystal phase. Our work is motivated by the need for strategies to engineer the magnetism of potentially half-metallic materials, such as NiMnSb, for improved performance at elevated temperatures. By means of ab initio calculations we investigate Ni1-xMn1+xSb over the whole composition range 0 <= x <= 1 of Ni replacing Mn and show that at relevant temperatures, the half-Heusler phase should be thermodynamically stable up to at least x=0.20 with respect to the competing C38 structure of Mn2Sb. Furthermore we find that half-Heusler Ni1-xMn1+xSb retains half-metallic band structure over the whole concentration range and that the magnetic moments of substitutional Mn-Ni atoms display magnetic exchange interactions an order of magnitude larger than the Ni-Mn interaction in NiMnSb. We also demonstrate experimentally that the alloys indeed can be created by synthesizing off-stoichiometric Ni1-xMn1+xSb films on MgO substrates by means of magnetron sputtering.

• 出版日期2010-11-1