STRONG INTERFACIAL MAGNETOELASTIC STRESS IN HOLMIUM-LUTETIUM(0001) SUPERLATTICES

The saturation magnetoelastic stress (MS), My, breaking the basal plan e cylindrical symmetry of the hexagonal structure, has been measured f or the series of superlattices (Ho-n/Lu-15) x 50(0001) (n = 8 to 85 at omic planes, with separation c/2). The MS was directly measured using a low-temperature cantilever technique. The Ho block MSs in the superl attices are larger than in an Ho film of 10(4) Angstrom thickness and in bulk Ho. An analysis accounting for the contributions to M-gamma co ming from: the volume, M-nu()(gamma), the interface, with magnetoelast ic parameter M-s(gamma) and the epitaxial strain shows that the interf acial magnetoelastic stress 2M(s)(gamma)/n(c/2) is strong, up to about six times larger than M-nu()(gamma) for n = 8, and of the opposite si gn.