Magnetotransport and magnetic properties of Fe-Cu, Fe-Ag, Fe-Au, and Fe-Pt alloys were studied across a wide range of Fe volume fraction and at different annealing conditions. The giant magnetoresistance (GMR) effect was observed in Cu-, Ag-, and Au-based systems, peaking at an Fe volume fraction of about 15–20 %. The Hall effect was also measured, which yielded the electron mean free path. Annealing systems of immiscible elements increase the magnetic particle size and reduce resistance due to magnetic scattering. The GMR and its dependence on magnetic field are well accounted for by an effective exchange interaction model.

• Received 19 January 1993

DOI:https://doi.org/10.1103/PhysRevB.47.8341