Ornstein-Zernike correlations and magnetic ordering in nanostructures Ever Alberto Velásquez, Johan Mazo-Zuluaga, Dora Altbir and José Mejía-López Eur. Phys. J. B, 87 3 (2014) 61 Published online: 10 March 2014 DOI: 10.1140/epjb/e2014-40712-6