|Budget Amount *help
¥2,100,000 (Direct Cost : ¥2,100,000)
Fiscal Year 1995 : ¥400,000 (Direct Cost : ¥400,000)
Fiscal Year 1994 : ¥1,700,000 (Direct Cost : ¥1,700,000)
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.