Magnetotransport properties of Fe3O4 nanocontacts

Abstract A piezo system is used to stabilize nanocontacts between two tiny crystals of the half metallic ferromagnet Fe 3 O 4 and their current–voltage characteristics are measured in a magnetic field. The non-linear I – V curves are fitted to an I = GV + cV 3 law. Large negative magnetoresistance effects of as much as 85% in a field of 7 mT are observed at room temperature, which increase with the resistance of the contact. The effect is discussed in terms of pinning a domain wall at the nanocontact.