Magnetic properties of iron clusters in Sc75Fe25 nanoglass

The magnetic and structural properties of Sc75Fe25 nanoglass prepared by Inert Gas Condensation and compression at 6 GPa are compared with Sc75Fe25 metallic glass produced by melt cooling. Nanoglass consists of nanometer sized glass regions connected by interfacial regions that have a non-crystalline structure. The magnetisation of Sc75Fe25 nanoglass was found to be about an order of magnitude larger than the magnetisation of Sc75Fe25 metallic glass (e.g., ~10 A m2 kg−1 cf. 0.4 A m2 kg−1 at 100 K respectively). The differences in magnetic behaviour of Sc75Fe25 nanoglass and Sc75Fe25 metallic glass result from the exceptional atomic structures of the interfacial regions in nanoglass with ferromagnetic Fe-clusters embedded in a Pauli paramagnetic matrix formed in the nanoglass interfacial regions. This in turn results in a reduction of the magnetic Fe-clusters in nanoglass with increasing external field, Bex; an effect that has not been observed previously in established magnetic materials. The distributions of Fe and Sc in Sc75Fe25 nanoglass and Sc75Fe25 metallic glass have been determined by scanning transmission electron microscopy; STEM based local radial distribution function (STEM-RDF) and electron energy loss spectroscopy (EELS).