INFLUENCE OF THE THICKNESS OF A NONMAGNETIC LAYER ON MAGNETIC-ANISOTROPY IN FEBSI/PD AND FEBSI/PD STRUCTURES

The magnetic anisotropy of multilayer structures of FeBSi/Si and FeBSi/Pd is studied as a function of the thickness t of the nonmagnetic medium. It is proposed that the uniaxial magnetic anisotropy with an easy axis in the film plane is created as a result of the stresses in the film which originate from the mismatch between the expansion coefficient of the substrate αs and that of the magnetic material αm. In the early stages of the film growth these stresses may enhance the structural processes typical for an amorphous state which are generally assumed to be the source of magnetic anisotropy. The experimental data indicate that the multilayer structure modifies the saturation magnetostriction constant λs. It is observed that λs depends on the thickness of the nonmagnetic layer t. Simultaneously, the uniaxial magnetic field Hu is found to be a function of t. The similar characters of both Kσ(t) and Ku(t) (Kσ and Ku are the stress-induced and experimentally obtained magnetic anisotropy constants respectively) suggest that the stresses in the film play an important role in the formation of the uniaxial magnetic anisotropy during the growth of amorphous multilayers. © 1990.