Uniform magnetization rotation in single ferromagnetic nanowires

Using electrochemical deposition, 6 mu m long Ni nanowires, with typical di ameters of the order of 80 nm, are grown in ion-track etched membranes. Ele ctrical contacts are established during the growth, allowing measurements o f single wires. The full magnetoresistive hysteresis loop is studied as a f unction of the angle between the applied field and the wire direction. For each field sweep, a discontinuity is observed. It corresponds to the irreve rsible switching of the magnetization. A model of uniform reversal of the m agnetization accounts for the reversible part of these magnetoresistive loo ps using the conventional cos(2)omega dependence of the resistance with the angle omega defined between magnetization and electric current. The angula r dependence of the switching field is discussed.