Theory of Spin Excitations and the Microwave Response of Cylindrical Ferromagnetic Nanowires

Abstract

We develop the theory of exchange/dipole spin wave excitations of ferromagnetic nanowires of cylindrical cross section, where the magnetization is parallel to the axis of the wire. In addition, we provide the theory of the microwave response of such structures, for the case where the nanowire is also a conductor. We present explicit calculations of both the mode structure of nanowires, and also their ferromagnetic resonance spectrum, with attention to recent experimental studies. We compare differences between the physical picture appropriate for the cylinder, with the well studied case of the ferromagnetic film.