Magnetic interactions in amorphous Fe-Sc alloys

Results of Fe-57 Mbssbauer spectroscopy, AC and DC susceptibility, grazing incidence X-ray diffraction and Rutherford-backscattering measurements on t he amorphous alloys Fe100-xScx(8 less than or equal tox less than or equal to 70) give for the first time, convincing evidence for the antiferromagnet ic exchange coupling between Fe moments at low Sc concentrations. This anti ferromagnetic coupling for 8 less than or equal tox less than or equal to 2 0 is limited to certain regions (magnetic clusters) of the sample. The natu re of the coupling is of the Heisenberg type. For x>43, the positive magnet ic coupling between the Fe moments is across Sc atoms. The ferromagnetic co upling between Fe atoms can be explained by the superexchange. Sc moments c ouple antiferromagnetically to the Fe nearest neighbors. (C) 2001 Elsevier Science B.V. All rights reserved.