Superparamagnetism in small Fe clusters on Cu(111) G. Ballentine, M. Heßler, M. Kinza and K. Fauth Eur. Phys. J. D, 45 3 (2007) 535-537 Published online: 26 September 2007 DOI: 10.1140/epjd/e2007-00271-9