Corredor, E.C. Coffey, D. Arnaudas, J.I. Ibarra, A. Ross, C.A. Ciria, M. Transverse magnetization in Cu/Ni/Cu epitaxial nanorings Eur. phys. j., B Cond. matter phys. 10.1140/epjb/e2013-30935-4 2013 2013