Joint Study on Metallic Artificial Superlattice

采用射频溅射法制备了（111）和（100）取向的Pd/Co-、Pd/PdCo-和Pd/ ni -多层膜。结果表明，晶体的垂直磁各向异性与晶体取向密切相关。在Pd/Co-和Pd/PdCo-(100)MLs中，只有当磁层很薄时才会产生垂直磁各向异性。在Pd/Ni-MLs中，（100）MLs的垂直磁各向异性大于（111）MLs。从磁弹性表面各向异性的角度讨论了各向异性产生的机理。根据诱导各向异性，估计了（111）取向多晶PdCo和PtCo合金膜和多层膜的磁致伸缩常数lambda_<111>和lambda_<100>。发现Pd/Co和Pt/Co MLs的磁致伸缩常数不受fcc Co的磁致伸缩常数的影响，而受PdCo和PtCo合金的磁致伸缩常数的影响较大。这一结果暗示了电子杂化和/或合金在界面处形成的影响。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10 ~ 15 a的双层周期内，垂直磁各向异性的最大值约为2.5X10^6 erg/cm_3。多层膜的磁光Kerr旋转达到0.33 400 nm，反映了Nd的贡献。报道了用射频磁控溅射法制备Fe_<16>Ni_<66>Co_<18>/Cu多层膜的巨磁阻效应。在300 K下，磁阻比可达35%，且随铜层厚度的变化而振荡。振荡周期约为1 nm，与Co/Cu多层材料的振荡周期相似。第一个峰的最大层间耦合强度约为0.05 erg/cm^2。对于第二个峰，耦合弱为0.003 erg/cm^2，磁阻比为13%。

Pd/Co-, Pd/PdCo- and Pd/Ni-multilayers (MLs) with (111) and (100) orientations have been prepared by the RF sputtering method. It was found that the perpendicular magnetic anisotropy of these MLs strongly depends on the crystal orientation. In both Pd/Co- and Pd/PdCo-(100)MLs, perpendicular magnetic anisotropy is induced only when magnetic layers are very thin. In Pd/Ni-MLs, perpendicular magnetic anisotropy is larger in (100)MLs than in (111)MLs. The mechanism of the anisotropy is discussed from the viewpoint of magnetoelastic surface anisotropy.Magnetostriction constants lambda_<111> and lambda_<100> were estimated for (111) oriented polycrystalline PdCo and PtCo alloy films and multilayer films (MLs) from the induced anisotropy. It was found that the magnetostriction constants of Pd/Co and Pt/Co MLs are not determined by the magnetostriction constants of fcc Co, but are strongly affected by those of PdCo and PtCo alloys. This result implies the effect of electron hybridization and/or alloy formation at the interface.Magnetic and magnetooptic properties have been investigated for NdGd/Fe and NdGd/FeCo multilayers prepared by rfsputtering method. At a bilayer period of 10 to 15 A, perpendicular magnetic anisotropy showed the maximum value of about 2.5X10^6 erg/cm_3. Magnetooptic Kerr rotation of the multilayers reach 0.33ﾟ at 400 nm, reflecting the contribution of Nd.The giant magnetoresistance effect of Fe_<16>Ni_<66>Co_<18>/Cu multilayers prepared by the RF magnetron sputtering method is reported. A magnetoresistance ratio as large as 35% is obtained at 300 K, and it oscillates as a function of Cu layer thickness. The oscillation period is about 1 nm, which is similar to the case of Co/Cu multilayers. The maximum interlayer coupling strength for the first peak is about 0.05 erg/cm^2. For the second peak the coupling is as weak as 0.003 erg/cm^2 with a magnetoresistance ratio of 13%.