Calculations of the First Ferromagnetic Anisotropy Coefficient, Gyromagnetic Ratio and Spectroscopic Splitting Factor for Nickel

Calculations are made of the first anisotropy coefficient K 1 and of the spectroscopic splitting factor g for nickel, based on the collective electron theory of the corresponding effects due to Brooks and the calculations of the author of the N ( E ) curve for the 3d electrons in nickel. Brooks' theory is reviewed, the underlying assumptions and approximations examined, some minor errors are corrected and it is extended to provide a formula for the gyromagnetic ratio g '. The value of - 5 × 10 7 erg cm -3 obtained for K 1 is considerably larger than the best available experimental value of - 8 × 10 5 ergs cm -3 for nickel at 0°K and Brooks' estimate of - 8 × 10 5 erg cm -3 . The values of 2.14 and 1.84 are obtained for g and g ' respectively as compared with experimental values of 2.19-2.42 and 1.93. Possible reasons for the discrepancies are discussed. Finally Brooks' theory is formally extended to remove one of the major approximations.