Role of anisotropy and interactions in magnetic nanoparticle systems R. Malik, S. Lamba, R. K. Kotnala and S. Annapoorni Eur. Phys. J. B, 74 1 (2010) 75-80 Published online: 23 February 2010 DOI: 10.1140/epjb/e2010-00065-x