Angular dependence of the coercivity and squareness of Fe50Co29Ni21 nanowire arrays

Abstract

Magnetic nanowires (NWs) electrodeposited into solid templates are of high interest due to their tunable properties which are required for magnetic recording media and spintronic devices. Here, we have paid particular attention to the angular dependence of magnetic properties on the applied magnetic field orientation. Highly ordered Fe50Co49Ni21 NW arrays with diameter of 50 nm and lengths of 32 and 54 μm were fabricated into nanopores of hardanodized aluminum oxide templates using pulsed ac electrodeposition technique. The coercivity and squareness of NWs were derived from hysteresis loops, measured at room temperature, as a function of angle between the field and wire axis. Investigation results of angular dependence of squareness demonstrate that the magnetic easy axis is along the NWs axis due to their large shape anisotropy. A non-monotonic behavior was found in angular dependence of coercivity, indicating a transition between the vortex and transverse reversal modes. Moreover, increasing length of NWs led to a decrease in the transition angle between the two reversal modes.