Argon and krypton ion-induced changes in permalloy thin films R. Gupta, K. P. Lieb, Y. Luo, G. A. Müller, P. Schaaf and K. Zhang Eur. Phys. J. B, 63 4 (2008) 501-506 Published online: 10 July 2008 DOI: 10.1140/epjb/e2008-00259-9