Magnetic and magneto optical characteristics of nanowire arrays embedded in anodic aluminium oxide

Abstract

Our recent work on the fabrication and properties of ordered elemental (Co, Fe) and alloy (Co1-xPtx) nanowire arrays embedded in anodic aluminium oxide (AAO) templates is reviewed. Nanowires with diameters from sub-micron to nano-metre have been fabricated using an electrodeposition technique. The nanowire array structure, crystallographic structure, magnetic properties, and magneto-optical properties have all been investigated. The wire size and photon energy dependent magneto-optical properties of Co and Fe nanowire arrays in the regime of visible spectrum were found to be considerably different from their bulk counterparts. The crystal structure of Co1-xPtx (0 < x ≤ 0.2) alloy nanowire arrays varies with the chemical composition: the c-axis is predominantly orientated for Co-rich Co1-xPtx wires and non-textured for pure Pt wires. Composition dependent squareness (Mr/Ms) and coercivity (perpendicular and parallel to the wire axis) have been observed. Furthermore, by rapid thermal annealing treatment, we found that nanowires with different composition showed different response to the annealing temperatures. The corresponding changes in crystal structure, the shape of hysteresis loops, saturation magnetization, coercivity, squareness and magneto-optical properties after annealing have been studied.