ABSTRACT
This chapter aims to clarifying the characteristic effects of nonuniform distribution of local fields on physical properties in amorphous magnets. The Mossbauer spectra of a large variety of amorphous magnetic alloys are very similar and consist of structureless absorption lines broadened by distributions of magnetic hyperfine fields and quadrupole and isomer shifts. Spins may also have local anisotropic fields originated from ligand Coulomb fields. In an amorphous magnet, the directions of these fields are random because of the random local environments. If the effect of local anisotropy is larger than the molecular field of each "sublattice", the spin-glass like ordering is energetically more favorable than antiferromagnetic one. The chapter shows that one prominent difference between the amorphous and crystalline ferromagnets concerns the temperature dependence of the susceptibility beyond the critical region; the downward curvature of the inverse paramagnetic susceptibility was temptingly ascribed as a characteristic of highly disordered systems.
