NANOSTRUCTURES, DISORDERED FERROMAGNETISM AND SPIN-GLASSES

Magnetic systems with a considerable amount of irregular interfaces we re investigated by Fe-57 Mossbauer spectroscopy. Chemically homogeneou s ferromagnets around the percolation threshold composition of disappe aring magnetism and chemically heterogeneous alloys prepared by nanocr ystallization of amorphous alloys belong to this class of materials. L ow temperature and high held measurements were performed on nanocrysta lline FeZrBCu alloys, on ball-milled Fe with nano-size grains and on m elt-quenched amorphous Fe-Zr and Fe-Y alloys in order to clarify the o rigin of large high-held susceptibility and to investigate the common features of the approach to magnetic saturation. Curie point determina tion of the residual amorphous phase in the nanocrystalline FeZrBCu al loys, results on the structure of the nanocrystalline b.c.c. phase and of the interfacial region will be reported.