CNM Research Highlighted in Scientific Journal
An article by Dr. Kristen Buchanan of the Electronic & Magnetic Materials & Devices Group at the Center for Nanoscale
Materials, and collaborators at Argonne's Advanced Photon Source, Cornell University, and University of Illinois - Chicago, was
recently featured on the cover of 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 by 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. (more...)
See V. Rose, X.M. Cheng, D.J. Keavney, J.W. Freeland, K.S. Buchanan, B. Ilic, and V. Metlushko, "The breakdown of the fingerprinting
of vortices by hysteresis loops in circular multilayer ring arrays,"; Appl.
Phys. Lett. 91, 132501 (24 September 2007).