Thickness dependence of giant magnetoresistance of Co20Ag80 granular films

The thickness dependence of magnetoresistance was studied for a series of thin Co20Ag80 films. The room temperature magnetoresistance in perpendicular configuration (CIP) was measured for as-deposited and annealed samples in fields up to 2 T. All samples were annealed for 10 min at temperatures ranging from 423 to 623 K at steps of 100 K. MR values growing with the thickness t were observed. MR varies steeply for small t and saturates at larger thicknesses. Changes of the width of the MR curve with the film thickness were also analyzed.