Magnetic properties of ordered arrays of iron nanowires: The impact of the length

The present study is focused on the investigation of the magnetic properties of hexagonally ordered iron nanowire arrays electrodeposited into anodic alumina templates. A series of 9 arrays of nanowires with a diameter of 52 nm, an interwire distance of 100 nm, and a length varying from 3.6 to 21.2 ?m is analyzed. Scanning electron microscopy, X-ray diffraction, SQUID magnetometry, and first-order reversal curves (FORC) analysis are used for the characterization of the nanowire arrays. The increase in coercivity with nanowire length is well described by a model of interacting wires, which are magnetized likely by a vortex domain wall mechanism. According to the width of distribution observed in the FORC diagrams, interaction fields decrease with increasing length, which supports the proposed model.