A Calculation on Pressure Dependence of Spin Wave Energy of Invar Alloys

Under the assumption that the change in volume of the system affects both the band width and molecular field coefficient but the shape of the density-of-states curve remains unaffected, a formula for the pressure dependence of exchange stiffness D is derived. For a system of two dimensional free electrons with step-type density-of-states curve, calculations on D and its pressure dependence dD/dp are performed with reasonable values of parameters. Calculated results well reproduce the observed composition dependence of the reduced values of D and dD/dp for fee Fe-Ni alloy system, while the calculated absolute values themselves are smaller by about an order of magnitude than the observed ones.Article信州大学理学部紀要 9(1): 43-53(1974)departmental bulletin pape

Electronic structure and magnetism of intermetallic mixed compound Mn₄N₁₋xCx

By applying the recursion method to the intermetallic mixed compound Mn₄N₁₋xCx with cubic perovskite-type structure we investigate the effects of substitution of C atoms for N atoms on the electronic structure and the magnetic properties of Mn₄N. By calculating the DOS's for the ferrimagnetic states of both Mn₄N and Mn₄N₀.₇₅C₀.₂₅ we have determined the magnetic moments at two types of Mn site, Mn(I)(corner site) and Mn(II) (face center site), which are antiparallel to each other. The obtained magnetic moment of Mn(I) in Mn₄N₀.₇₅C₀.₂₅ is found to be the same with that in Mn₄N while the absolute value of Mn(II) moment increases by the substitution of C atoms. As the result the total ferromagnetic moment decreases by the substitution of C atoms. These results are in good agreement with the observations.Article信州大学理学部紀要 30(1): 25-36(1995)departmental bulletin pape