Thin Cr-capped Co films (thickness 50150) have been grown epitaxially on GaAs(001) single-crystal substrates by molecular-beam epitaxy. In contrast to other investigations, transmission electron diffraction reveals that the epitaxial Co films have a hexagonal-close-packed (hcp) structure with the epitaxial relationships (1»21»0)Co(001)GaAs and (1»21»0)Co(001)[1»10]GaAs, i.e., the c axis of each crystallite is assigned to either the in-plane  or the [1»10] direction of the GaAs(001) substrate. In-plane magneto-optical Kerr-effect hysteresis loops and Brillouin light-scattering measurements show that the thinnest epitaxial hcp Co film (50) has a dominant fourfold anisotropy with easy axes along the in-plane 100 directions and that a uniaxial anisotropy becomes dominant with increasing film thickness. We are able to account for the magnetic anisotropy properties of these epitaxial Co films in terms of their oriented hcp microstructure. © 1995 The American Physical Society.
|Number of pages||4|
|Journal||Physical Review B: covering condensed matter and materials physics|
|Publication status||Published - 1995|