A PHENOMENOLOGICAL MODEL FOR GIANT MAGNETORESISTANCE HYSTERESIS IN MAGNETIC DISCONTINUOUS MULTILAYER FILMS

A simple phenomenological model for giant magnetoresistance (GMR) is e mployed for current and field parallel (CIP) to the magnetic multilaye r planes in ordinary and discontinuous multilayer films, To our knowle dge, it is the first model to include hysteresis in the field (H) depe ndence of the GMR. The computed GMR versus H curves qualitatively repr oduce the GMR hysteresis seen experimentally, In particular, two GMR p eaks are found to be symmetrically placed about H=0, and the GMR hyste resis curve itself is found to have an inverted butterfly shape, Also seen in the computed results is the general increase in GMR magnitude found for annealed discontinuous multilayer films, Various parameter v ariations are examined in the computed results, While the model reprod uces GMR hysteresis quite well and the general increase in GMR for dis continuous multilayer films, it does not, in its present form, account for the oscillations seen in the GMR when the nonmagnetic layer thick nesses are varied, which is expected as a strictly quantum mechanical result.