Magnetic reversal modes in cylindrical nanowires

Abstract

We perform a systematic study based on micromagnetic simulations of the demagnetization process for cylindrical nanowires with different crystalline structure. These simulations correspond to the most commonly reported electrodeposited nanowires, based on permalloy, nickel, iron and cobalt, with crystal structure tailored by electrodeposition parameters. The dependence of coercivity and remanence on the nanowire diameter, the angular dependence of coercivity and the corresponding reversal modes are calculated and discussed. Extensive comparison of the obtained coercive field value with available experimental data is presented. Depending on the crystallographic structure, the nanowires reverse magnetization by transverse or vortex domain walls and can exhibit the vortex structure along the whole nanowire length. The state diagrams for reversal modes in different materials as a function of the exchange correlation length, nanowire diameter and the anisotropy direction are presented. Magnetic force microscopy images corresponding to different structures are also evaluated by the micromagnetic simulations.