In this work we study the magnetic properties of Permalloy (Py: Fe20Ni80) films grown as multilayers with thin Molibdenum (Mo) spacers, in order to optimize it for sensor applications. Properties like permabillity or linearity of the loops can be controlled by growing Py as a multilayer with alternating perpendicular anisotropies [2]. However for thicknesses over 180 nm sputtered Py films develop perpendicular anisotropy (induced by the columnar morphology of the sputtered films) and the magnetic properties degrade notably [3]. Both coercive and saturating fields are nearly 10 times bigger than those measured for thinner films. Nevertheless, we found that it is possible to obtain low coercivity and high permability if thick Py films are grown as multilayers with a non-magnetic spacer between magnetic layers. In addition, we studied the effect of the layers thicknesses in the coercive field which is minimum for a Py thicknesses about 30 nm
