INFLUENCE OF MICROSTRUCTURE ON MAGNETORESISTANCE OF FEAG GRANULAR FILMS

The magnetoresistance of FeAg granular films with optimum composition has been systematically studied as a function of film thickness. It wa s found that the giant magnetoresistance increases rapidly with increa sing film thickness in the initial stage, and beyond about 500 Angstro m the improvements become limited. The saturation field was also found to rise with increasing film thickness. Transmission electron microsc ope studies showed that with the increase of film thickness the micros tructure becomes more homogeneous, with smaller. grains and fewer stru ctural defects such as twins. A discussion of the influence of microst ructure on magnetoresistance and saturation field is presented.