MAGNETIC-FLUX MEASUREMENT OF COBALT NANOWIRES BY ELECTRON HOLOGRAPHY

Off-axis electron holography has been used to measure and to visualize the magnetic flux of magnetic cobalt nanowires, synthesized by electr odeposition in porous membranes. As a result it is evident that the ma gnetic field of a single nanowire can be understood as a superposition of magnetic dipoles oriented along the nanowire axis. The magnetic fl ux of single cobalt nanowires was found to correspond to integer multi ples of Phi=h/e, i.e. the magnetic flux of nanowires is quantized. We checked that the phase change measured was actually only due to the ma gnetic field, by taking a second hologram after reversing the specimen upside down.