Magnetic Properties of Artificial Super Lattice and its Application for magneto-optical Recording Media

人工超结构和复合调制多层材料往往表现出增强的磁各向异性，其轴线容易垂直于薄膜平面，这种各向异性在磁性和磁光记录等应用中非常有吸引力。在本研究中，我们研究了两种类型的多层材料的磁性能，一种是贵金属(Nm) /过渡金属（TM）多层材料，另一种是稀土(RE) /含轻稀土的过渡金属多层材料，与普通的TbFeCo合金相比，它们在短波长具有磁光克尔效应的优势。采用射频溅射法制备了NM （Pd, Pt, Cu, Au, PdSi）层和TM （Co, Ni, PdCo, PtCo, CoZr）层。研究了垂直磁各向异性与磁致伸缩、晶格失配、晶体度和晶体取向的关系。结果表明，纳米/PdCo合金多层膜的垂直磁各向异性来源于PdCo层在晶格失配应力作用下的磁弹性能。在Pd/Co和Pd/Ni多层材料中，各向异性都与晶体取向有关，这种关系可归因于这些合金的各向异性磁致伸缩常数。研究了用射频溅射法制备的nddd /Fe和nddd /FeCo多层膜的磁性和磁光性能。在双层周期为10 ~ 15 A时，垂直磁各向异性达到最大值，约为2.5 X 10^6 erg/cm^3, 400 nm处磁光Kerr旋转达到0.33，反映了Nd的贡献。

Artificially superstructured as well as compositonally modulated multilayers show often enhanced magnetic anisotropy with the easy axis perpendicular to the film plane, and this anisotropy is very attractive in applications such as magnetic and magneto-optic recording. In this research, we have investigated magnetic properties in two type of multilayers, one is noble metal (Nm) /transition metal (TM) multilayer, the other is rareearth (RE) /transition metal containing light RE, which have advantage to magnetooptic Kerr effect at short wavelength compared with usial TbFeCo alloy.I. NM/TM multilayersMultilayers consists of NM (Pd, Pt, Cu, Au, PdSi) and TM (Co, Ni, PdCo, PtCo, CoZr) layers were prepared by rf sputtering method on glass and/or MgO single crystal substrates. The perpendicular magnetic anisotropy was examined in relation to the magnetostriction, lattice misfits, crystanity and crystal orientations. The results suggest that the perpendicular magnetic anisotropy in NM/PdCo-alloy multilayers originates from the magnetoelastic energy of the PdCo layers under a stress due to the lattice misfits. In both Pd/Co and Pd/Ni multilayers, the anisotropy, was found to depend on the crystal orientation, and the dependence could be attributed to the anisotropic magnetostriction constants of these alloys.II. RE/TM multilayersMagnetic and magneto-optic properties have been investigated for NdGd/Fe and NdGd/FeCo multilayers prepared by rf sputtering method. At bilayer period of 10 to 15 A, perpendicular magnetic anisotropy showed the maximum value of about 2.5 X 10^6 erg/cm^3, magneto-optic Kerr rotation in the multilayers reach 0.33 at 400 nm, reflecting the contribution of Nd.