Prediction of half-metallic properties for the Heusler alloys Mn2CrZ (Z=Al, Ga, Si, Ge, Sb): A first-principles study
Prediction of half-metallic properties for the Heusler alloys Mn2CrZ (Z=Al, Ga, Si, Ge, Sb): A first-principles study
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DOI：
10.1016/j.jmmm.2007.06.021
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发表时间：
2008-02
影响因子：
2.7
通讯作者：
Hongzhi Luo;Zhiyong Zhu;Guodong Liu;Shifeng Xu;Guangheng Wu;Heyan Liu;J. Qu;Yangxiang Li
中科院分区：
文献类型：
--
作者：
Hongzhi Luo;Zhiyong Zhu;Guodong Liu;Shifeng Xu;Guangheng Wu;Heyan Liu;J. Qu;Yangxiang Li
对Mn2CrZ(Z=Al，Ga，Si，Ge和Sb)合金进行了第一性原理FLAPW计算。在这些结果的基础上，我们预测了两种半金属铁磁体，即Mn2CrAl和Mn2CrSb，并在Mn2CrGa中发现了一个位于费米能级附近的能隙。Mn2CrAl和Mn2CrGa的能隙位于大部分自旋能带，而Mn2CrSb的能隙位于少数自旋能带。计算的总自旋磁矩Mtcale分别为−1μBPER晶胞，+1μBPER晶胞，Mn2CrSb和Mn2CrGe，符合斯莱特-鲍林定律。计算表明，铬在B位有较大的局域磁矩。这对于在Heusler合金中寻找新的半金属反铁磁体具有重要意义。结果表明，铬的磁矩随原子序数的增加而增大，与锰的磁矩成反比。当Z原子改变时，Mn和Cr自旋矩的变化相互补偿，使总的自旋矩保持为一个整数。
First-principles FLAPW calculations were performed on the Mn2CrZ (Z=Al, Ga, Si, Ge and Sb) alloys. Based on these results we predict two half-metallic ferromagnets (HMFs) namely Mn2CrAl and Mn2CrSb, and also find an energy gap in Mn2CrGa which lies near the Fermi level. The energy gap lies in the majority spin band for Mn2CrAl and Mn2CrGa, whereas in the minority one for Mn2CrSb. The calculated total spin magnetic moments Mtcalare −1μBper unit cell for Mn2CrAl and Mn2CrGa, +1μBper unit cell for Mn2CrSb and zero for Mn2CrSi and Mn2CrGe, which agree with the Slater–Pauling rule. The calculation indicates a large and localized magnetic moment of Cr at B site. This is meaningful for searching for new half-metallic antiferromagnets in Heusler alloys. The magnetic moment of Cr is found to increase with increasing atomic number of Z and is antiparallel to that of Mn. The change of Mn and Cr spin moments compensates each other and keeps the total spin moment as an integer when the Z atom is changed.