ELECTRONIC STRUCTURES AND MAGNETIC PROPERTIES OF COMPOUNDS INCLUDING P,As AND TRANSITION ELEMENTS

含 P、As 和过渡元素的化合物的电子结构和磁性

基本信息

批准号：
06640485
负责人：
ISHIDA Shoji
金额：
$ 1.34万
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：
1994
资助国家：
日本
起止时间：
1994 至 1995
项目状态：
已结题

项目摘要

Electoronic structures of CrMX (M=Fe, Co, Ni : X=P,As) were calculated to examine the magnetic properties, where the crystal structure is the Fe_2P type for CrMAs and the Co_2P type for CrMP.From the density of state (DOS) for a nonmagnetic state, we can guess that Cr in CrMX carries a magnetic moment but M atom does not even though pure metals of Fe, Co and Ni are ferromagnets. It will also be shown that although M atom is nonmagnetic, the magnetism of CrMX changes with M atom because the hybridization between d states of Cr and M atoms affects Cr d bands. Comparing the DOS and total energies for para- (PA), ferro- (F) and antiferromagnetic (AF) state, we found that the most stable state is the F state for CrNiP,CrFeAs and CrNiAs, the AF state for CrFeP and CrCoAs and the PA state for CrCoP.However, our results suggest that the three magnetic states are competitive in CrCoAs. These theoretical results correspond well the experimental ones.The experimental values of the local magnetic moment are 0.55 and 0.65mu_B for Cr and Ni in CrNiAs respectively, while our results are 1.19 and 0.11mu_B and so Cr carries most of the moment. The theoretical value of the lattice constant is in good agreement with the experimental one.Half-metallic (HM) compounds were also searched and were predicted theoretically as foolows.1.Ru_2MnZ (Z=si, P,Sn) are antiferromagnets, but become HM in ferromagnetic phase.2.Changing the number of valence electrons of Z atom in Co_2MnZ (Z=IIIb, IVb, Vb atom) and TMnZ (T=Pd, Rh : Z=Sb, Te), we can find HM compounds.3.If TMnZ (T=Ir, Pt, Pd, Rh, Z=Sb, Te) are presed, they become HM.

计算了 CrMX (M=Fe, Co, Ni : X=P,As) 的电子结构以检查磁性能，其中 CrMAs 的晶体结构为 Fe_2P 型，CrMP 的晶体结构为 Co_2P 型。对于非磁性状态，我们可以猜测 CrMX 中的 Cr 带有磁矩，而 M 原子则不带有磁矩，尽管 Fe、Co 和 Ni 的纯金属是铁磁体。还将表明，虽然M原子是非磁性的，但CrMX的磁性随着M原子的变化而变化，因为Cr和M原子的d态之间的杂化影响了Cr d带。比较对位（PA）、铁（F）和反铁磁（AF）态的DOS和总能量，我们发现CrNiP、CrFeAs和CrNiAs的最稳定态是F态，CrFeP和CrCoAs的最稳定态是AF态然而，我们的结果表明，CrCoAs 中的三种磁性状态是相互竞争的。这些理论结果与实验结果吻合良好。CrNiAs中Cr和Ni的局部磁矩的实验值分别为0.55和0.65mu_B，而我们的结果为1.19和0.11mu_B，因此Cr承载了大部分磁矩。晶格常数的理论值与实验值吻合较好。还搜索了半金属（HM）化合物，并进行了理论上的预测。1.Ru_2MnZ（Z=si，P，Sn）是反铁磁体，但变成铁磁相HM。2.改变Co_2MnZ（Z=IIIb、IVb、Vb原子）和TMnZ中Z原子的价电子数(T=Pd,Rh : Z=Sb,Te)，我们可以找到HM化合物。3.如果存在TMnZ(T=Ir,Pt,Pd,Rh,Z=Sb,Te)，则它们成为HM。