Study on the origin of induced magnetic anisotropy of metal-insulator nano-granular soft-magnetic film by small-angle X-ray and neutron scattering

为了实现高密度和快速的电子器件，需要在GHz频段具有高磁导率的软磁材料。纳米颗粒软磁薄膜具有高的饱和磁化强度、大的电阻率和大的感生磁各向异性场Hk，有时甚至超过200Oe，因此是很有前途的候选材料之一。除大HK外，合金性能的主要来源是由几乎纯的Co和Si-O基非晶基质组成的显微组织。ELK也表现出对平均粒径的弱依赖性，但尚未发现微观结构各向异性。为了充分理解各向异性的起源，需要知道小于Hk的磁场中的磁化过程。为此，我们使用小角中子散射(SANS)。我们的研究结果如下：1.SANS的强度最大值平行于磁化的长轴。这表明磁化强度…的贡献很小垂直于主磁化轴方向的离子越多。当施加垂直于易轴的磁场时，强度最大值向外场连续旋转，表明小的贡献也与磁化的主要成分一起旋转。次要成分的磁畴大小随外场的变化而变化。在小场地中较大，在靠近BK的场地中较小。后者为10 nm左右，仍大于颗粒大小(~3 nm)。主要成分的磁畴尺寸大于几千纳米，这是我们SANS测量的最大尺寸。因此，这表明在软磁材料中存在层次型结构，这种层次型结构在软磁材料中从未见过报道。因此，它可能是显示大BK的关键因素。为了证实这一点，我们现在正在进行进一步的实验，使用更强的中子源，从2008年12月开始。较少

For achieving high density and fast electronic devices, soft magnetic materials with high-magnetic permeability at the GHz frequency regions are required. Nano-granular soft-magnetic films are one of the promising candidates because of their high saturation magnetization, large resistivity and large induced magnetic anisotropy field, Hk, that sometimes exceed 200 Oe. Except large Hk, the origin of the properties is attribute to the microstructure which consists of almost pure Co and Si-O base amorphous matrix. Elk also shows weak dependence of the average particle size, however, no microstructural anisotropy has been found yet. For full understanding of the origin of anisotropy, it is needed to know the magnetization process in the field smaller than Hk. For this purpose, we use small-angle neutron scattering (SANS). Our findings are follows;1. Intensity maximum in SANS appears parallel to the major axis of magnetization. This indicates the existence of minor contribution of magnetizat … More ion which lies perpendicular direction to the major magnetization axis.2. By applying magnetic field perpendicular to easy axis, the intensity maximum rotate continuously to the external field, indicating the minor contribution also rotate together with major component of magnetization.3. The size of the magnetic domain of minor component is changed by the external field. Larger in the small field and smaller in the field close to the Bk. Latter ease, it is about 10 nm which is still larger than the particle size (〜3nm). Magnetic domain size of the major component is larger than a few thousand nm that is the maximum size of our SANS measurements. Therefore, it indicates the existence of hierarchical structure in the magnetic domain.Such of hierarchical structure in the magnetic domain has never reported in the soft-magnetic materials. Hence it can be a key factor for showing large Bk. For confirming it, we are now conducting further experiments using stronger neutron source which starts from Dec. 2008. Less