Electronic Structures of Laves Phase Compounds

Laves相化合物的电子结构

基本信息

批准号：
59540188
负责人：
ISHIDA Shoji
金额：
$ 0.77万
依托单位：
Kagoshima University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1984
资助国家：
日本
起止时间：
1984 至 1986
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-59540188/
关键词：
Laves phase compound Electronic structure Magnetism 結晶構造の安定性

项目摘要

The Laves phase compounds have the three types of crystal structures: hexagonal C14 and C36 and cubic C15. The more than 200 with these structures compounds have been found. The magnetism are full of variety, which has not been observed in the other compounds. The aid of this project is to investigate the relation between the magnetism and electronic structures. The following results have been obtained.(1) Band calculations were carried out for the compounds between transition metals and the density-of-states (DOS) and the magnetic moments were obtained. We can guess the magnetism (para, ferro or antiferromagnetism) from the position of the Fermi level in the paramagnetic DOS.(2) The crystal structure of Laves compounds A <B_2> is mainly determined by the B atom: the crystal structure is the C14 type when the B atom is Cr, Co or Ni (Mo, Rh or Pd) and the C15 structure when the B atom is Mn or Fe (Tc or Ru). The magnetism is concerned with the structure when this rule cannot be applied.(3) The band width of the B atom changes delicately by the A atom. When the A atom changes in the order Y, Zr, Nb that is, the magnetism of the B atom becomes strong in the order Nb, Zr, Y.(4) The same tendency is seen when the atom is substituted from a 4d transition metal to a 3d transition metal. The band width of the B atom is widened. Therefore, the enegy gain due to the spin polarization decreases and Ti <Fe_2> exhibits antiferromagnetism although Zr <Fe_2> exhibits ferromagnetism.

Laves相化合物具有三种类型的晶体结构：六边形C14和C36和Cubic C15。已经发现了200多个具有这些结构化合物的。磁性充满了多样性，在其他化合物中尚未观察到。该项目的帮助是研究磁性和电子结构之间的关系。已经获得了以下结果。（1）对过渡金属和态密度（DOS）之间的化合物进行了带计算，并获得了磁矩。我们可以猜测费米水平的位置的磁性（para，para，para，para，para，para，para，para，para，para，para，para或抗磁磁性）。（TC或RU）。磁性与无法应用此规则时的结构有关。（3）B原子的带宽度通过A原子微妙地变化。当a原子在y，zr，nb的顺序变化时，b原子的磁性在nb，zr，y的顺序中变得强大。（4）当原子从4D过渡金属代替到3D过渡金属时，也可以看到相同的趋势。 B原子的带宽扩大。因此，尽管Zr <fe_2>表现出铁磁性，但由于自旋极化而引起的e弱增益降低，Ti <FE_2>表现出抗fifer磁性。