ABSTRACTWe have investigated the structural properties of Ni80Fe20 thin films sputtered on silicon with Cr, Ta and SiO2 buffer layers using transmission electron microscopy. We observe a decrease of the grain size when Ta and SiO2 underlayers are used instead of Cr. Permalloy films deposited on Ta layers are strongly (111) textured while those grown on Cr and SiO2 are mostly randomly oriented. The results are discussed with respect to the nanostructure of both Ta, Cr and SiO2 underlayers and in relation to the variation of the magnetic softness observed in this system.