Co掺杂对Ni-Mn-Sn合金磁特性影响:第一性原理研究

通过第一性原理计算,研究Co元素掺杂对Ni-Mn-Sn合金态密度和晶格参数的影响规律。研究表明,Co的加入改变了合金费米能级处自旋向下态密度的分布,形成有利于结构稳定的赝能隙,对自旋向上的态密度影响较小。随着Co元素的增加,合金晶胞体积收缩,价电子浓度降低,晶胞母相总磁矩增大,原来合金中部分Ni3d-Mn3d杂化经掺杂后被Co3d-Mn3d杂化替代。这些因素使合金母相更加稳定,马氏体相变温度降低。

Effect of Co substitution on the magnetic behavior of Ni-Mn-Sn alloys:first-principle study

The effect of Co-substitution on the state density and lattice parameters for Ni-Mn-Sn alloy was studied by the first principle. The result shows that, the substitution of Co changes the distribution of the density of spin downwards at the Fermi energy level, forming a pseudo energy gap which is beneficial to the stability of the structure. It has little effect on the density of spin upwards of Ni-Co-Mn-Sn parent phase. More Co3d-Mn3d hybridization replacing Ni3d-Mn3d hybrids was found with the increase of Co substitution for Ni. Moreover, the cell volume reduces continuously. These factors make the parent phase of the alloy more stable, which is the primary reason for the martensitic transformation temperature decreasing.