Fabrication of self-assembled lateral nanostructures and their applications for magnetic materials

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Magnetic nanostructures with lateral modulation were prepared by molecular beam epitaxy and UHV magnetron sputtering, and their magnetic, magnetotransport and magnetooptical properties etc. were investigated. The main results obtained in this study are as follows:1.Self assembled Fe nanoparticles were formed on a thin MgO layer which is epitaxially grown on a Fe buffer with an optimum thickness, and it was found by scanning tunneling microscopy observations that the Fe nanoparticles were alingned in a [110] direction. Cross sectional high-resolution electron microscopy observation suggested that an aligned pyramid structure of the Fe buffer caused the lateral alignment of Fe nanoparticles.2.Preparation of FePt films on FeAl single crystal surfaces with nano.pores were attempted by using both bulk and thin film processes. Magnetic properties of obtained FePt films were measured and the effects of pores on properties of FePt films were systematically investigated.3.By optimized heat treatments for alternate stacking of FePt and MgO, tetrahedral FePt nanoparticles embedded partially in MgO were successfully synthesized. The formed FePt nanoparticles showed a large coercive force, suggesting an application of magnetic probe microscopy.4.Novel surface structures such as rectangular holes and network structures were successfully prepared for NiO thin films by oxygen reactive sputtering. The observed structures are expected to be used for a template for lateral nanostructures.5.Surface phase separation was investigated for ultrathin Fe-Au alloys deposited on a Pt(100) surface. A few kinds of novel lateral nanostructures were observed by scanning tunneling micropcopy.