N. Mori

Anisotropy energies for Y2Fe14B and Nd2Fe14B

The approximate d bands for Y2Fe14B and Nd2Fe14B are formulated by Deegan’s prescription and the formulas of Slater and Koster. The electronic energies of these crystals with the spin directions [001], [100], [101], and [110] are calculated by Gilat and Raubenheimer’s method. The experimental result of the anisotropy energy for Y2Fe14B is analyzed with use of these calculated results by introducing the differences of the number of d electrons for these four states. In Nd2Fe14B the same differences of the number of d electrons are introduced and the contribution to the anisotropy energy due to 4f electrons is deduced. This contribution is analyzed by the use of the crystalline field potential (the localized model) and the band model with d‐f elements derived by Lendi. The obtained results are considered to be reasonable.

On the orbital moment of Co in YCo5

Abstract The experimental result of the orbital and spin moments for Co in YCo 5 is analyzed by the use of the approximate d bands for YCo 5 . The calculation of the anistropy constants K u1 and K u2 is worked out. Finally, the contributions to the anistropy constants due to 3d bands of Co I , those of Co II , those of Co I and Co II , and 3d and 4d bands of Co I , Co II and Y are discussed.

Calculation of anisotropy constants

Abstract Accurate calculation is made for the anistropy constants for Ni, Co and Fe metals by using Gilat and Raubenheimers method in d band model. The obtained result is in agreement with the experimental result. Additionally, the anisotropy constants for Ni-based alloys, Co-based alloys and Gd metal are calculated.

Anisotropy energy of Y2Fe14B, Y2Co14B, Y2Fe14−xCoxB, and La2Co14B

The anisotropy energies of Y2Fe14B, Y2Co14B, Y2Fe14−xCoxB, and La2Co14B are discussed with reference to the band model. The energy bands exclusive and inclusive of the p bands in B are formulated in consideration of the spin‐orbit interaction and exchange splitting. The anisotropy constant K1 is estimated through the difference between the calculated electronic energies with the magnetization parallel to [001] and [100]. In Y2Fe14B, the calculated K1 is much the same as the experimental result, and in Y2Co14B, it agrees with the experimental result. In Y2Fe14−xCoxB, the calculated K1 inclusive of the p bands in B is much the same as the experimental result. Finally, the anisotropy energy of La2Co14B is discussed by taking into account the 4f bands just above the Fermi level.The anisotropy energies of Y{sub 2}Fe{sub 14}B, Y{sub 2}Co{sub 14}B, Y{sub 2}Fe{sub 14{minus}{ital x}}Co{sub {ital x}}B, and La{sub 2}Co{sub 14}B are discussed with reference to the band model. The energy bands exclusive and inclusive of the {ital p} bands in B are formulated in consideration of the spin-orbit interaction and exchange splitting. The anisotropy constant {ital K}{sub 1} is estimated through the difference between the calculated electronic energies with the magnetization parallel to (001) and (100). In Y{sub 2}Fe{sub 14}B, the calculated {ital K}{sub 1} is much the same as the experimental result, and in Y{sub 2}Co{sub 14}B, it agrees with the experimental result. In Y{sub 2}Fe{sub 14{minus}{ital x}}Co{sub {ital x}}B, the calculated {ital K}{sub 1} inclusive of the {ital p} bands in B is much the same as the experimental result. Finally, the anisotropy energy of La{sub 2}Co{sub 14}B is discussed by taking into account the 4{ital f} bands just above the Fermi level.

A band theory of magnetic structure of α-and β-manganese

Abstract Based on the Hubbard-like Hamiltonian, a tight binding calculation was made to determine both the magnetic moments and their directions on 29 atoms in the symmetric unit cell of the antiferromagnetic α-Mn metal. The densities of the local magnetic moments and the local densities of states were also calculated.

On the magnetic structure of noncollinear γ‐Fe70Mn30

The approximate d bands for a noncollinear γ‐FeMn alloy are formulated by using Deegan’s method and the formulas of Slater and Koster, and by taking into account the exchange interaction terms to produce the multi‐spin‐density‐wave state. The electronic energies for the noncollinear γ‐Fe70Mn30 alloy with the spin directions parallel to [100], [110], and [111] are calculated and the anisotropy energy is determined. It is seen that the state with the spin direction [111] becomes the lowest and the multi‐spin‐density‐wave state is realized in it. For other noncollinear γ‐FeMn alloys some discussions are given on the magnetic structure for them. Additionally, the anisotropy energies for noncollinear and collinear γ‐FeMn alloys are discussed in detail.

On the appearance of ferromagnetism in Y(Co1−xAlx)2 alloys

Abstract The appearance of ferromagnetism in Y(Co 1− x Al x ) 2 is discussed in terms of a d band model. The approximate d bands for YCo 2 and Y(Co 1− x ) 2 are calculated and the decrease in the electronic energy due to magnetization of the spin of estimated. The energy decrease is the largest in YCo 2 , and it gradually decreases as the Al content increases, if the lattice constant is fixed, while this energy decrease increases if the lattice constant increases with increasing Al content. These results of calculations give a good account of the appearance of ferromagnetism in Y(Co 1− x Al x ) 2 around x = 0.15. The ferromagnetism in Sc(CO 1− x Al x ) 2 is also discussed, leading to the appearance of ferromagnetism between x = 0.15 and 0.30.

On the anisotropy energies for YCo5 and PrCo5 compounds

The approximate d bands for YCo5 and PrCo5 compounds are formulated by Deegans prescription. The experimental result for the anisotropy energy of YCo5 compound is analyzed by a d band model. The anisotropy energy for PrCo5 compound is also analyzed in the same way as that for the YCo5 compound, and the contributions due to 4f electrons are deduced. This contribution can be interpreted by the crystalline field theory with the use of a moderate crystalline field potential.

On the magnetism of Au4Ti, Au4V, Au4Cr, Au4Mn, Au8TiCr, and Au8VMn

It is pointed out that the energy decrease due to the magnetization of the spin is large in the ferromagnetic substances and that the energy decrease due to the formation of the antiferromagnetic disposition is large in the antiferromagnetic substances. The calculation is made for the energy decrease in the ferromagnetic state as a function of the number of d electrons. This calculation explains the paramagnetic Au4Ti, the weak ferromagnetic Au4V, and the ferromagnetic Au4Mn. The energy decrease for Au5 and Au3V2 is also calculated, and it is shown that ferromagnetism appears in the vicinity of Au4V. The calculation is made for the energy decrease in the antiferromagnetic state as a function of the number of d electrons. This calculation suggests that antiferromagnetism appears in Au4Cr. The anisotropy energies for Au4V and Au4Mn are calculated to be in agreement with the experimental result. It is shown that the magnetic moment in Au4Cr should be parallel to [001] direction. Finally, the magnetism of Au8...

On the temperature dependence of the periodicity of the SDW state in the Cr metal

Abstract The temperature dependence and the pressure effect of the periodicity of the SDW state and the phenomenon ‘spin-flip’ for Cr metal are investigated on the basis of the d bands for the SDW state, by using Gilat-Raubenheimers method. The experimental results are well explained.