Magnetic states of an individual Ni nanotube probed by anisotropic magnetoresistance

Defined magnetization states in magnetic nanotubes could be the basic building blocks for future memory elements. To date, it has been extremely challenging to measure the magnetic states at the single-nanotube level. We investigate the magnetization states of an individual Ni nanotube by measuring the anisotropic magnetoresistance effect at cryogenic temperature. Depending on the magnitude and direction of the magnetic field, we program the nanotube to be in a vortex- or onion-like state near remanence. The magnetoresistance measured on an individual Ni nanotube is shown to reflect characteristic magnetic states which make the nanoscale tubular geometry interesting for memory applications.