THERMAL-STABILITY OF NDGD FECO MULTILAYERS

Thermal stability has been investigated for the structure and the perp endicular anisotropy K(u) of Nd44Gd56/Fe89Co11 multilayer films with t he bflayer period of 1 nm, where K(u) becomes the maximum. From the re sults of isothermal annealing at temperature T(a), it has been found t hat the saturation magnetization M(s) scarcely changes up to T(a) = 40 0-degrees-C, while K(u) is almost constant up to T(a) = 200-degrees-C but decreases rather quickly for T(a) above 200-degrees-C. The decreas e in K(u) for T(a) >260-degrees-C is accompanied by the decrease in th e peak intensity of low angle x-ray diffraction, namely by the deterio ration of the layered structure.