A method for creating a magnetically permeable film on a substrate surface by deposition of successive layers of a magnetic material, during deposition of each layer a magnetic field being provided near said surface having a field direction substantially parallel to the surface. In order to tune the permeability of the magnetic material the method builds up the magnetically permeable film by forming each layer by depositing a ferromagnetic material to a thickness maximally corresponding to substantially ##EQU1## where L.sub.ex is equal to ##EQU2## with A being the exchange constant of the ferromagnetic material and K.sub.u being the uniaxial anisotropy constant, and changing the magnetic field direction during formation of said layer by an angle other than substantially 180.degree..