Interaction Effects in Ni Nanowire Arrays

Systems of magnetic nanowires are considered strong candidates in many technological applications as microwave filters, sensors or for data storage. The main parameter that controls the response of magnetic nanowires assemblies is the aspect ratio of the nanowires. In this paper we modify the aspect ratio by keeping constant the length of nanowires and modifying the nanowires´ diameter. Ni nanowires with diameters of 40, 60, 80 nm and constant lengths of 1000 nm and 500 nm were grown with a standard electrodeposition technique in Anodized Aluminum Oxide (AAO) membranes. The samples were studied using vibrating sample magnetometer and X-band ferromagnetic resonance experiments at room temperature. As the nanowire diameter increases, the coercive field increases and also two different types of dependence of resonance field versus aspect ratio were observed. The results are explained taking into account the effects of the magnetostatic interactions and shape anisotropy.