Magneto transport properties of Fe3O4 nanocontacts

A piezo system is used to stabilize nanocontacts between two tiny crystals of the half metallic ferromagnet Fe3O4 and their current-voltage characteri stics are measured in a magnetic field. The non-linear I-V curves are fitte d to an I = GV + cV(3) law. Large negative magnetoresistance effects of as much as 85% in a field of 7mT are observed at room temperature. which incre ase with the resistance of the contact. The effect is discussed in terms of pinning a domain wall at the nanocontact. (C) 2001 Elsevier Science B.V. A ll rights reserved.