Magnetic vortex and single domain states in transition metal nanodot arrays prepared by Talbot lithography and electrodeposition

Abstract

We report the first results of the growth of nickel and permalloy (Ni80Fe20) circular nanodot arrays with a dot diameter of 300 nm using Talbot lithography and electrochemical deposition. Samples with different thicknesses (50 nm to 400 nm) and, thus, aspect ratios were prepared by the variation of deposition times. The magnetization reversal and the associated magnetic configuration were probed by vibrating sample magnetometry (VSM) and magnetic phase diagram was plotted for both nickel and permalloy nanodot arrays. We observe a transition from a uniform magnetisation in the inplane direction to a vortex state followed by a uniform magnetisation to the out of plane direction, with an increase in thickness of the dots. The magnetic phase diagram in dependence on the dot geometry is in good agreement with micromagnetic simulations and for sputtered structures. We also probe the magnetic vortex states in permalloy nanodot arrays using Kerr microscopy and further aim to magneto-ionically control the magnetic states in our dot arrays.