title: Spin-glass freezing and RKKY interactions near the metal-insulator transition in amorphous Gd-Si alloys
abstract: Magnetization measurements of giant negative magnetoresistive amorphous GdxSi1-x ( 0.04<x<0.19) show strong mixed ferromagnetic and antiferromagnetic interactions and spin-glass freezing. The interactions appear to be an RKKY-like indirect exchange mediated by the conduction electrons, but are strikingly independent of their localization at the metal-insulator (MI) transition, presumably because the localization length exceeds the inter-Gd distance. The susceptibility per Gd atom in the paramagnetic state shows a nontrivial dependence on composition, with a maximum at the MI transition.
authors.affiliation: Department of Physics, University of California, San Diego, California 92093, USA.
authors.initials: F
authors.lastname: Hellman
authors.initials: DR
authors.lastname: Queen
authors.initials: RM
authors.lastname: Potok
authors.initials: BL
authors.lastname: Zink