Co/Cr superlattices with Co layer thickness of 15 Å and Cr layer thickness of 10 Å have been successfully grown on different substrates, such as MgO, Si, and quartz, by molecular-beam-epitaxy. The crystal structure of all samples has been characterized by in situ reflection high-energy electron diffraction. Both magnetoresistance (MR) and magneto-optical Kerr effect (MOKE) measurements were used to analyze the magnetic properties of these samples. Excellent epitaxial growth of hcp-Co(1100)/bcc-Cr(211) superlattices grown on MgO(110) was observed. Co/Cr superlattices were polycrystalline when grown on Si and amorphous when grown on quartz. Isotropic MRs of less than 1% were observed for all polycrystalline and amorphous Co/Cr superlattices. For Co(1100)/Cr(211) superlattices grown on MgO(110), a transverse MR of 14.2% and longitudinal MR of 0.67% were observed. MOKE hysteresis loops show perpendicular magnetization for polycrystalline Co/Cr superlattices grown on Si, and in-plane isotropic magnetization for amorphous Co/Cr superlattices grown on quartz. MOKE hysteresis loops for Co/Cr superlattices grown on MgO(110) show strong anisotropic behavior between the hard and easy directions. The magnetic properties of Co/Cr superlattices are strongly influenced by the crystal structure of Co and Cr which is controlled by the substrate.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)