THE INFLUENCE OF FILM THICKNESS ON MAGNETORESISTANCE AND MAGNETIC-PROPERTIES OF FEAG GRANULAR FILMS

The influence of film thickness on magnetoresistance and magnetic prop erties of FeAg granular films has been systematically studied. It was found that both the giant magnetoresistance and the saturation field i ncrease with increasing film thickness. Magnetic measurements indicate d that with increasing film thickness, the average size of magnetic pa rticles as well as the coercivity H-c changes considerably. The evolut ion of the granular size is ascribed to the increasing precipitation o f ultrafine iron particles during sputtering, which, to some extent, s erves as an in situ annealing. The magnetic properties have been inten sively discussed in terms of superparamagnetism.