Magnetic anisotropy distribution near the surface of amorphous ribbons

Magnetic anisotropy in an amorphous ribbon of Fe40Ni40P14B6has been studied. Domain structures and the in-plane anisotropy were measured as a function of the depth from the ribbon surface by a powder technique, transmission electron microscopy and a torque method. Groups of fine domains diminish with depth. The maximum in-plane anisotropy exists at the surface and the anisotropy decreases one or two orders in magnitude at the center of the ribbon. The data have an obvious connection with the surface topography of the ribbon that is introduced in the melt and quench process.