Magnetic anisotropy and reorientation in Co/Rh superlattices

摘要

Co/Rh multilayers have been grown at different substrate temperatures in UHV by molecular beam epitaxy (MBE). The Co thickness ranges between 3 and 9 /spl Aring/, while the Rh thickness is fixed at 9 W. In situ RHEED and X-ray diffraction measurements reveal an epitaxial growth of these films on the fcc (111) Rh buffer layer. From polar hysteresis loop measurements we find that a magnetic reorientation from a perpendicular to in-plane direction occurs in these films at around 4 Co-layers at room temperature, and at around 2 Co-layers at 456 K. From our measurements we estimate the second order volume anisotropy K/sub V/ /spl ap/10/sup 7/ erg/cm/sup 3/, and the surface anisotropy K/sub S//spl ap/0.3 erg/cm/sup 2/ at room temperature. The nature of the magnetic reorientation is discussed. As far as we know this is the first report on the existence of the magnetic reorientation phenomenon in Co/Rh superlattices as a function of film thickness and temperature.