Zero-temperature spin-glass freezing in self-organized arrays of Co nanoparticles R. López-Ruiz, F. Luis, J. Sesé, J. Bartolomé, C. Deranlot and F. Petroff EPL, 89 6 (2010) 67011 Published online: 19 April 2010 DOI: 10.1209/0295-5075/89/67011