Magnetic nanoscale aggregates of cobalt and nickel in MgO single crystals J. V. Pinto, M. M. Cruz, R. C. da Silva, E. Alves, R. González and M. Godinho Eur. Phys. J. B, 45 3 (2005) 331-338 Published online: 06 July 2005 DOI: 10.1140/epjb/e2005-00202-8