GIANT MAGNETORESISTANCE IN AG CO MULTILAYERS IRRADIATED BY EXCIMER-LASER/

Ag/Co multilayers (MLs) showing the giant magnetoresistance (GMR) were prepared by electron beam evaporation in UHV at room temperatures ont o Si/SiO2 substrates. The samples were thermally processed by excimer laser irradiation at the fluences F = 0.1, 0.15 and 0.2 J cm(-2) and n umber of pulses between 1 and 200. The samples were analyzed by X-ray diffraction (XRD) and grazing incidence (GI)XRD. The electrical resist ance R(H) was measured up to 50 kOe with magnetic field perpendicular or parallel to the film plane and with current in plane of the multila yers at 4.2 K. Two different types of MLs were studied. In one of them [(2 nm Ag/l nm Co) x 5], Ag layers melt under laser irradiation accor ding to our numerical computations and the change of GMR is non-system atic. In the other MLs [(6 nm Ag/l nm Co)x 5] the Ag and Co layers don 't melt and the GMR increase vs. deposited laser energy is almost syst ematic. This effect is ascribed to the transformation of continuous Co layer into discontinuous one with larger inter-facial area between no n-magnetic and magnetic components in the ML. (C) 1998 Elsevier Scienc e S.A.