Probing the magnetic properties of cobalt–germanium nanocable arrays

Abstract

We report the synthesis of high density arrays of coaxial nanocables, consisting of germanium nanowires surrounded by cobalt nanotube sheaths, within anodic aluminium oxide membranes. The nanocable arrays were prepared using a supercritical fluid inclusion process, whereby the cobalt nanotubes were first deposited on the pore walls of the nanoporous membranes and subsequently filled with germanium to form coaxial nanocables. The composition and structure of the metal–semiconductor nanostructures was investigated by electron microscopy, energy dispersive X-ray mapping and X-ray diffraction at high angles. The magnetic properties of the co-axial nanocables were probed using a superconducting quantum interference device (SQUID). In essence, this paper describes a technique for merging semiconductor and magnetic technologies into well-defined building blocks which may ultimately lead to new multifunctional devices, such as spin-field effect transistors.