Fabrication and Magnetoresistance of Single Au-Ni-AuNanowire

Magnetoresistance of Au-Ni-Aunanowire with 300 nm long nickel segment sandwiched between the gold segmentsis studied. Structural analysis of the sample is performed by X-ray diffraction and transmission electron microscopy, which reveals the pure phase, crystalline behavior of the nanowires. Magnetic measurements of the samples confirm ferromagnetic behavior due to the presence of nickel in the wires. Current versus voltage measurement of single nanowire bridged between the two gold electrodes shows ohmic behavior at room temperature with a resistance of 73 Ω. Magnetoresistance as a function of the applied field shows a decreasing trend of resistance below 140 Oe, followed by an increasing trend in resistance in the field range 140 Oe50 Oe, and finally attains a saturation value for the fields >250 Oe. The results have been explained with reference to the variation of magneto-resistance upon the alignment of spins, formation of magnetic domains and their propagation along the direction of magnetic field.