MORPHOLOGICAL-CHANGES INDUCED BY THERMAL ANNEALS IN NIFE AG MULTILAYERS - THEIR RELATION TO THE RESISTIVE AND MAGNETORESISTIVE PROPERTIES/

X-ray diffraction and simulation were used to characterize the morphol ogical evolution that takes place in permalloy/silver (NiFe/Ag) multil ayers as the result of thermal annealing. Auger spectroscopy, electron microscopy, resistivity and magnetoresistivity measurements were perf ormed in order to obtain additional insight into the results. The resu lts are consistent with the model of Ag grain boundary diffusion takin g place along the columnar grains, leading to the creation of so-calle d 'silver bridges' between the permalloy grains. The initial stages of annealing (up to 633 K) result in formation of individual NiFe grains that leads to enhanced values of the magnetoresistivity. Annealing at higher temperatures causes the growth of relatively large Ag and NiFe agglomerates and results in breakup of the original multilayered stru cture. (C) 1997 Elsevier Science S.A.