THE EFFECT OF DEPOSITION PROCESS ON THE MAGNETIC-PROPERTIES OF COUPLED PERMALLOY THIN-FILMS

Double layer thin films of permalloy (layer thickness 200-1300 angstro m) with tantalum (50 angstrom) as a nonmagnetic spacer have been prepa red by e-beam evaporation. The effect of deposition parameters, especi ally the substrate temperature on the magnetic properties of these fil ms has been examined. The coercivity(Hc) of the double layer films was found to be very sensitive to the substrate temperature in the permal loy layer thickness range of 200-600 angstrom. The coercivity of the f ilms deposited at 40-degrees-C is lower than at 300-degrees-C and is a lmost independent of the Permalloy layer thickness. The XRD patterns a nd STM images of these two films exhibit large differences in permallo y grain size and grain orientation. However, the Hc of the single laye r films deposited under the same conditions as the double layer films shows no significant change in this thickness region. The results indi cate that the change of interface condition is primarily responsible f or the Hc variation in the coupled films deposited at different substr ate temperatures and strongly suggest that interface roughness plays a dominant role in the coupling between the permalloy layers.