FINITE-TEMPERATURE THEORY OF NONCOLLINEAR MAGNETISM IN AMORPHOUS FE

Noncollinear magnetism in the vicinity of amorphous Fe has been invest igated by developing the finite temperature theory of amorphous metall ic magnetism which takes into account the transverse spin fluctuations . The theory is based on the functional integral technique to the dege nerate-band Hubbard Hamiltonian with Hund's rule coupling and the dist ribution function method for local magnetic moments with structural di sorder. It is shown that an isotropic spin-glass is realized in amorph ous Fe, by taking into account the transverse components of local magn etic moments. The origin of the spin-glass around amorphous Fe is expl ained by the nonlinear magnetic couplings between Fe local moments and the local environment effects on the amplitude of Fe local moments. W hen the d electron number N is increased, the isotropic spin-glass cha nges to a noncollinear ferromagnet at N=7.40 and finally changes to a collinear ferromagnet beyond N=7.47 at 35 K. (C) 1997 American Institu te of Physics.