STRAINED LAYERS AND MAGNETOELASTIC COUPLING

Very large internal strains (of order 1 to 10%) may exist in thin films and at the surfaces of magnetic materials. These strains obviously couple through magnetoelastic (ME) constants to contribute significantly to magnetic anisotropy energy density. It is less widely appreciated, but not less important, that in the presence of such large strains the ME constants themselves are changed. We have measured the surface ME coupling coefficients in two amorphous alloys and found them to differ significantly from bulk values. The implications of such results for surface, thin film and interface anisotropy are discussed.