Detection of Local Oersted Field Generated at the Junction Between Ferromagnetic Nanowire and Electrode

We report local concentration of the Oersted field at the junction of electric contact geometry. The local Oersted field is numerically calculated with a simplified analytical model. This local field is then verified experimentally by observing magnetization reversal due to the current injection into Permalloy nanowires under magnetic field bias. The threshold current of magnetization reversal is found to be linearly dependent on the strength of the magnetic-field bias with a proportional coefficient (6.9 ± 0.2) × 10^-11 Oe·m²/A, which provides evidence of the local concentration of the Oersted field at the junction.