Enhanced anisotropy of permalloy layers sputter deposited on V-grooved substrates and tilted surfaces

The magnetic anisotropy of 8–100 nm thick Ni80Fe20 films sputter deposited on nanostructured V-grooved substrates and on tilted surfaces is investigated. Films deposited on a V-grooved substrate (200 nm period) with the sidefaces at an angle of 55° to the substrate plane, show a very large and essentially thickness-independent magnetic anisotropy field, viz. 25±3 kA/m. Planar reference films deposited also at an angle of 55° to their substrate normal show an increase of the magnetic anisotropy as well, but only to 8 kA/m, independent of the film thickness, which is explained as a growth-induced effect. It is argued that the enhanced anisotropy observed in the V-grooved substrates is not the result of shape anisotropy induced by the V-grooves. This leads to the conclusion that the observed enhanced anisotropy must also be a growth-induced effect, enhanced by the specific geometry of the V-grooves.