Electromagnetic properties of ferromagnetic nanowire arrays

A general model for the effective permeability and permittivity tensors of ferromagnetic nanowire arrays, based on a Maxwell-Garnett homogenization procedure, is proposed and incorporates the effects of the geometric parameters of the array, the shape of the wires, and their intrinsic dielectric and magnetic properties. Effective external tensors, which include the dynamic dipolar dielectric and magnetic interwire interactions, are then derived to provide a link between the effective susceptibilities of the array and those measured in microwave cavity experiments. The emphasis is put on the prediction that ferromagnetic nanowire arrays may exhibit simultaneously gyromagnetic and magnetodielectric responses, which are both tunable by an external static magnetic field. (C) 2008 American Institute of Physics.