MBE GROWTH OF MAGNETIC NANO-WIRES ON OFF-CUT SUBSTRATES AND ITS APPLICATION TO MAGNETIC NANO-DEVICES

研究了 MBE 生长的 Co/Pt 超晶格的磁各向异性。薄膜在 MgO (100) 和 (111) 衬底上外延生长，分别为 MgO (100)、[010]//Ag、Co/Pt (100)、[010] 和 MgO (111)、[110]//Ag、Co/Pt [110]。垂直各向异性强烈依赖于薄膜取向。 RHEED 的结构分析表明 (100) 薄膜的 Co 平面存在较大的拉伸应变。与（111）薄膜相比，（100）薄膜表现出更大的负体积各向异性，这是通过分析薄膜平面中的各向异性能量发现的正磁致伸缩常数各向异性来解释的。 (100)和(111)薄膜分别表现出四重和六重对称性的面内各向异性，并且随着Co/Pt超晶格中Co厚度的减小，它们的值显着增强。通过MBE方法在加热的MgO(100)和(111)基底上生长了Pt合金薄膜。结果发现，在300℃的温度下，在(111)衬底上生长出具有CuPt型结构的薄膜。由于沿薄膜法线方向的层状结构，各向异性为 1.0×10D16D1 J/m2D13D1。 CuPt结构薄膜的克尔旋转θD2kD2光谱与AuCu结构有很大不同，在4.0eV附近没有出现最大值，但在1.4eV处出现峰值。

Magnetic anisotropy in MBE grown Co/Pt superlattices were investigated. The films were epitaxially grown on MgO (100) and (111) substrates as MgO (100), [010]//Ag, Co/Pt (100), [010] and MgO (111), [110]//Ag, Co/Pt [110], respectively. The perpendicular anisotropy were strongly dependent on the film orientation. Structural analysis by RHEED revealed the existence of a large tensile strain in the Co plane of the (100) films. The (100) films exhibit larger negative volume anisotropy compared to the (111) films, which is explained by the magnetoelastic effect through the positive magnetostriction constant λィイD2100ィエD2 of fcc Co. The large magnetocrystalline anisotropy was found by the analysis of the anisotropy energy in the film plane. The (100) and (111) films showed in-plane anisotropy with four fold and six fold symmetry, respectively and their values were considerably enhanced with decreasing Co thickness in Co/Pt superlattices.PtィイD250ィエD2CoィイD250ィエD2 alloy films have been grown by MBE method onto heated MgO (100) and (111) substrates. It is found that the film with CuPt type structure is grown onto (111) substrate at a temperature of 300゜. Whereas, the crystal structure of the films grown onto (111) substrate at 500゜ and onto (100) substrate at 300゜ and 400゜ becomes PtCo ordered phase with AuCu structure. The film of the CuPt type exhibits a very large perpendicular magnetic anisotropy of 1.0×10ィイD16ィエD1 J/mィイD13ィエD1, due to the layered structure along the film normal direction. The spectrum of Kerr rotation θィイD2kィエD2 of the film with CuPt structure is considerably different from that of AuCu structure, not exhibiting a maximum around 4.0 eV but takes a peak at 1.4 eV.