THICKNESS DEPENDENCE OF MAGNETIZATION AND MAGNETOSTRICTION OF NiFe AND NiFeRh FILMS

The saturation magnetization, 4πMs, and the magnetostriction constant, λ, of Ni81Fe19, Ni81Fe19/Ta and Ni72Fe17Rh11/ Ta thinfilms were studied as a function of film thickness before and after annealing. For films of thickness t < 200 Å, 4πMs, and λs were found to be strongly dependent on film thickness with even larger variation after annealing. Auger depth profiles have shown the existence of inhomogeneous interfacial layer at the film surface, Ta/film and film/substrate interfaces. The presence of such layers of different composition and magnetic properties from the film bulk, can explain the observed behavior of 4πMs and λs