Effect of annealing and additive agent on magnetoresistance properties of pulse plated Cu–Co nano-granular alloys

In this report, magnetization and magnetoresistance properties of pulse (PC) and direct current (DC) deposited Cu–Co alloy films containing 37 at.% of cobalt and higher were investigated. Magnetization measurements revealed, even at high cobalt content, the co-existence of superparamagnetic (SPM) nano-granules along with FM regions. Addition of saccharine within the electrolyte led to a reduction in the coercivity of the films but annealed samples had opposite effect on it. Room temperature magnetoresistance (MR) measurements showed resistance change due to anisotropic magnetoresistance (AMR) of the as-deposited films. Upon annealing, several times increase of MR was noticed with the appearance of typical giant magnetoresistance (GMR) behavior. A maximum negative GMR of 3.2% was obtained for annealed pulse plated Cu62.5Co37.5 alloy film. For DC plated samples, addition of saccharine had noticeable effect on GMR compared to PC plated alloys.