Correlation between electrical, galvanomagnetic and magnetic properties of nanocrystalline iron films obtained by ion assisted deposition

Abstract

Here we present the measurements of the temperature dependence of resistance, transverse and longitudinal magnetoresistance (MR) in nanocrystalline iron films in the temperature range 2-300 K and the sweep of the magnetic field up to 8 T. Thin nanocrystalline films of α-iron phase with 80 nm thickness were obtained by ion-beam assisted deposition on a silicon substrate. In addition to the shape anisotropy, the obtained iron films exhibited perpendicular magnetic anisotropy (PMA), which disappeared after annealing the films at a temperature of 450oC in a vacuum. The effect of PMA on the sign and magnitude of the MR of iron films, as well as on the magnetic field dependences of the magnetoresistive effect, recorded at different orientations of the external magnetic field with respect to the film plane and current direction, is experimentally shown. The results obtained are discussed in the framework of modern views on the processes of charge transfer in a weakly disordered ferromagnetic films with different magnetic anisotropy and domain structure when a weak (less than the saturation field of magnetization) or strong (higher than the saturation field) external magnetic field is applied. Keywords: nanocrystalline iron films, perpendicular magnetic anisotropy, magnetoresistance, anisotropic magnetoresistance, magnon magnetoresistance, percolation, weak localization.