Competing magnetoresistance contributions in sputtered FePt thin films

Fe-Pt thin films were deposited by rf sputtering on an MgO substrate heated at different temperatures to induce the formation of the perpendicular Fe-Pt L10 phase with a different grain morphology on the nanometer scale. All films are characterized by a mazelike pattern of FePt nanograins with interconnected bases. MFM images and magnetization curves indicate that all samples have a strong perpendicular magnetic anisotropy arising from (0 0 1) growth. The temperature behaviour of the electrical resistance indicates that a percolating path exists for conduction electrons in the mazelike pattern. The magnetoresistance was measured as a function of magnetic field (applied longitudinally) and temperature in the ranges −70 kOe