Finite-size effects in giant magnetoresistance multilayers

It is of interest to determine the characteristic length scale that determi nes giant magnetoresistance (GMR). In order to understand this behavior, GM R multilayers of Co/Ru and Co/Cu have been studied at a temperature of 4.2 K. The total thickness of Co/Ru multilayers has been varied from 96 to 1654 Angstrom and Co/Cu from 77 to 2712 Angstrom by increasing the number of bi layers (N). It has been observed that GMR increases with the number of bila yers and more than 20 bilayers for Co/Ru and 50 for Co/Cu are needed to rea ch the saturation value. (C) 2001 American Institute of Physics.