SPIN RELAXATION EFFECTS IN THE PERPENDICULAR MAGNETORESISTANCE OF MAGNETIC MULTILAYERS

The spin-diffusion length is the scaling length of the perpendicular g iant magnetoresistance in magnetic multilayers and, according to recen t experiments, the magnetoresistance ratio can be significantly reduce d by enhancing the spin relaxation and thus shortening the spin-diffus ion length. We present a theoretical picture of these spin-diffusion-l ength effects on the magnetoresistance. We also calculate the contribu tion from several mechanisms (spin-orbit scattering, exchange scatteri ng by paramagnetic impurities, electron-magnon scattering) to the spin relaxation and spin-diffusion length.