Applied Physics Letters
Microscale single-layer ferromagnetic rings typically exhibit a magnetic vortex state at remanence, characterized by a flux-closed magnetic state with zero stray fields. Magnetic reversal in such systems yields a vanishing remanent magnetization. In contrast, the authors show that in individual layers in thin rings, which alternate magnetic and nonmagnetic materials (NiFe/Cu/Co), layer-resolved hysteresis loops, measured using x-ray resonant magnetic scattering, exhibit the characteristics of a vortex formation, although photoelectron emission microscopy and micromagnetic simulations clearly prove that multidomain states are formed. This result is of considerable importance for the development of pseudo-spin-valve-type structures for applications.
Copyright (2007) American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Appl. Phys. Lett. 91, 132501 (2007), and may be found at http://prl.aps.org/abstract/PRL/v98/i11/e117204.
V. Rose et al., Appl. Phys. Lett. 91, 132501 (2007).