Fabrication and magnetic properties of 100-nm-scaled permalloy nanotube arrays

Abstract

Fabrication and magnetization characteristics of permalloy nanotube arrays that are in 100-nm-scale have been demonstrated. Permalloy nanotube array is made by using a standard electron-beam lithography combining with an ion-beam milling process. Geometric parameters of individual permalloy nanotube are fixed to be 300/20 nm for outer diameter/wall thickness, and the heights are varied from 180 to 600 nm. Height dependent magnetization reversal behaviors are investigated by using longitudinal magneto-optical Kerr effect with the external field applied perpendicular to the tubular axis. Micromagnetic simulations are performed to scrutinize the micromagnetization configurations. Up to two pairs of head-to-head and tail-to-tail domain walls on both tubular ends and vortex structure motion on the sidewall are identified during the magnetization reversal.