ANOMALOUS LOW-ANGLE X-RAY-DIFFRACTION IN SPUTTER-DEPOSITED FE/CR MULTILAYERS AND ITS RELATION TO THE GIANT MAGNETORESISTANCE

Low-angle X-ray diffraction analysis was carried out on the [Fe(30 angstrom)/Cr (10 angstrom)]22 thin films prepared by two-gun magnetron sputtering under various argon pressures. It turned out that the magnetoresistance (MR) of these films was very sensitive to the argon pressure during sputtering. According to X-ray analysis it seemed that at low argon pressures (< 20 mTorr) intermixing of each layer occurred and at high pressures (> 40 mTorr) the layers became fluctuating, which caused a splitting of the low-angle X-ray peaks. A layer fluctuation model (LFM) is suggested to explain the existence of the optimum argon pressure (in terms of the MR) in this artificial superlattice.