Single-crystal Co(1120)/Cr(100) superlattices (SLs) have been successfully grown on MgO (100) and Al 2 O 3 (1102) substrates with 100 Å Mo as buffer layers by molecular beam epitaxy (MBE). Excellent epitaxial growth was evidenced by reflection high-energy electron diffraction (RHEED). Magneto-resistance (MR) measurements have been performed using a conventional four-point technique. We have observed negative MR (NMR ≈ 4.8%) for [Co(40 Å)/Cr(5 Å)] 70 SLs, giant positive MR (PMR ≈ 30%) for [Co(5 Co )/Cr(5 Å)] 100 SLs. It is likely that the NMR effect is introduced by the Co/Cr SL while PMR is induced by the Mo buffer layers. Interestingly, PMR samples show a distinct roughness effect compared to NMR samples. Systematically we have found that NMR increases with increasing interfacial roughness, while PMR samples show the opposite behavior.
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Physics and Astronomy(all)
- Surfaces and Interfaces
- Surfaces, Coatings and Films