MAGNETIC AND FERROMAGNETIC-RESONANCE STUDIES IN CO-CU COMPOSITE FILMS

Co1-xCux composite films with 0 less-than-or-equal-to x less-than-or-e qual-to 83 have been sputter deposited on to water-cooled glass substr ates. Transmission electron microscopy and scanning tunneling microsco py studies reveal clusters whose average size is 250 angstrom. Magneti zation when corrected to the Co volume is independent of Cu concentrat ion and is equal to that of bulk Co. The in-plane saturation field is about 200 Oe at x = 0, starts increasing for x = 40, and shows a peak value of 1.2 kOe for x = 60. Coercivity shows a similar behavior. Out- of-plane perpendicular anisotropy develops with the increase in Cu con centration. The ferromagnetic resonance studies show that (i) the line width increases for x>75 and (ii) perpendicular anisotropy, probably i nduced by stress, also increases with x. Annealing up to 300-degrees-C does not produce any noticeable changes but when annealed at 400-degr ees-C the perpendicular anisotropy decreases indicating some stress re lief.