Design of magnetic materials: the electronic structure of the ordered, doped Heusler compound Co2Cr1−xFexAl
Design of magnetic materials: the electronic structure of the ordered, doped Heusler compound Co2Cr1−xFexAl
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DOI：
10.1088/0953-8984/17/46/008
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发表时间：
2005-10
期刊：
影响因子：
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通讯作者：
G. Fecher;H. Kandpal;S. Wurmehl;J. Morais;Hong‐ji Lin;H. Elmers;G. Schönhense;C. Felser
中科院分区：
文献类型：
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作者：
G. Fecher;H. Kandpal;S. Wurmehl;J. Morais;Hong‐ji Lin;H. Elmers;G. Schönhense;C. Felser
实验和理论研究了不同Cr/Fe比x的掺杂Heusler化合物Co2 Cr 1 −xFexAl。使用不同类型的能带结构计算计算了有序掺杂Heusler化合物Co2 Cr 1 −xFexAl（x = n/4，n = 0，1，2，3，4）的电子结构。有序的化合物原来是铁磁性的小铝磁矩反平行排列的3d过渡金属的时刻。所有化合物在少数带的费米能级附近都存在能隙。纯化合物表现出间接的少数间隙，而有序的，掺杂的化合物表现出直接的间隙。在纯化合物和x = 0.4合金的Co、Fe和Cr的L2，3边缘处测量X射线吸收光谱中的磁性圆二色性，以确定元素特定的磁矩。计算和测量表明，随着铁含量的增加，磁矩增加。实验观察到的Cr的磁矩的减少可以解释由Co-Cr网站的障碍。Co2 CrAl少数带中差距的存在是由于L21结构中存在纯Co2和混合CrAl（001）面。它保留在具有不同顺序的CrAl平面的结构中，但在具有交替的CoCr和CoAl平面的X结构中消失。
The doped Heusler compounds Co2Cr1−xFexAl with varying Cr to Fe ratio x were investigated experimentally and theoretically. The electronic structure of the ordered, doped Heusler compound Co2Cr1−xFexAl (x = n/4,n = 0,1,2,3,4) was calculated using band structure calculations of different types. The ordered compounds turned out to be ferromagnetic with the small Al magnetic moment aligned antiparallel to the 3d transition metal moments. All compounds show a gap around the Fermi energy in the minority bands. The pure compounds exhibit an indirect minority gap, whereas the ordered, doped compounds exhibit a direct gap. The magnetic circular dichroism in the x-ray absorption spectra was measured at the L2,3 edges of Co, Fe, and Cr of the pure compounds and the x = 0.4 alloy in order to determine element-specific magnetic moments. Calculations and measurements show an increase of the magnetic moments with increasing iron content. The experimentally observed reduction of the magnetic moment of Cr can be explained by Co–Cr site disorder. The presence of the gap in the minority bands of Co2CrAl can be attributed to the occurrence of pure Co2 and mixed CrAl(001) planes in the L 21 structure. It is retained in structures with different order of the CrAl planes but vanishes in the X structure with alternating CoCr and CoAl planes.