In this paper, we present a complete three-dimensional characterization of vortex core spin structures, which is important for future magnetic data storage based on vortex cores in disks and in wires. Using electron holography to examine vortices in patterned Permalloy devices we have quantitatively measured the in-plane and out-of-plane magnetization of a vortex core. Observed core widths and integrated phase shifts agree well with those derived from micromagnetic simulations.
Bibliographical noteFunding Information:
The authors acknowledge support by the Deutsche Forschungsgemeinschaft (SFB 513), Landesstiftung Baden Württemberg, and the EPSRC (UK). One of the authors (F.J.) acknowledges support by the “Studienstiftung des Deutschen Volkes,” D.B. acknowledges support by the European Union (Interreg III A program), R.E.D.B. acknowledges support by the Royal Society, and J.M.F. thanks NERC (UK) for financial support.