EPITAXIAL STRAIN, METASTABLE STRUCTURE, AND MAGNETIC-ANISOTROPY IN CO-BASED SUPERLATTICES

We explore the relationship between interface structure and magnetic anisotropy in three types of Co-based superlattices: Co(hcp)-Au; Co(fcc)-Cu; and Co(hcp)-Cr, grown epitaxially on GaAs(110). For very thin layers of Co, Co-Au, and Co-Cu superlattices exhibit a perpendicular easy axis due to magnetoelastic contributions to the anisotropy energy. The magnetic anisotropy in Co-Cr is found to be strongly dependent on growth conditions. At slow deposition rates of Co the interface between Co and Cr becomes diffuse as is evidenced by a low saturation moment and a shift toward perpendicular anisotropy whereas samples with abrupt interfaces show predominantly parallel anisotropy. The Cr layers grow in a metastable hcp phase which appears to be paramagnetic. The results illustrate the influence of the heterointerface on magnetic properties.