Influence of annealing on magnetoresistance of Co/Cu multilayers

A correlation between magnetoresistance and magnetic properties of as-depos ited and annealed Cu/Co multilayers, produced by magnetron sputtering, has been discussed. Two models have been proposed to describe the shapes of mag netoresistance and magnetization hysteresis loops: one taking into account the multidomain structure of the layers and another based on dissimilar mag netic properties of the Fe buffer layer and Co layers. A difference between the initial magnetoresistance and the hysteresis peak as a function of the annealing temperature has been explained in terms of magnetization process es. The annealing treatments of the films with 2.2-nm Cu spacer at temperat ures between 300 and 340 degreesC increased the magnetoresistance hysteresi s peak to 43% compared to 30-35% for the as-deposited samples. This value r emained high even after l-h annealing at 380 degreesC and the GMR at room t emperature decreased only by 27% compared to the low temperature one. (C) 2 000 Elsevier Science S.A. All rights reserved.