Arrays of Ni nanowires in alumina membranes: magnetic properties and spatial ordering M. Vázquez, M. Hernández-Vélez, K. Pirota, A. Asenjo, D. Navas, J. Velázquez, P. Vargas and C. Ramos Eur. Phys. J. B, 40 4 (2004) 489-497 Published online: 15 June 2004 DOI: 10.1140/epjb/e2004-00163-4