Study on Evolution of Ferromagnetism in Metal Thin Films in Monolayer Regime

本研究的目的是阐明磁性薄膜在单层区域的表面磁性的来源。为此，我们用自旋分辨光电子能谱和角分辨光电子能谱研究了磁性和非磁性晶体表面上生长的固体表面和磁性薄膜的电子结构。在本项目期间，我们研究了(1)Ni单晶表面作为典型的铁磁表面之一，(2)Co(001)表面上已知形成fcc和bcc铁的Fe膜，(3)有望表现出随膜厚变化的磁各向异性的Co薄膜，以及(4)一些外延生长的磁性薄膜，如MNAs，MnSb等。阐明了(1)Ni自旋相关的价带结构和电子相关效应，(2)Co和Cu表面Fe薄膜从fcc到bcc的厚度依赖结构变化，(3)Au(111)表面Co薄膜的结构和电子性质与其磁各向异性的关系。

The aim of this research project is to clarify the origin of the surface magnetism of magnetic thin films in monolayer regime. To this end we have investigated electronic structures of solid surfaces and magnetic thin films grown on magnetic and non-magnetic crystal surfaces by means of spin- and angle-resolved photoelectron spectroscopy.Within the period of the project, we have studied on (1) Ni single crystal surface as one of a typical ferromagnetic surface, (2) Fe films on Co(001) surfaces, which are known to form fcc as well as bcc iron, (3) Co thin films which are expected to reveal film-thickness dependent magnetic anisotropy and (4) some epitaxially grown magnetic thin films such as MnAs, MnSb, etc. As results, we have clarified (1) on Ni spin dependent valence band structures and electron correlation effects appeared there, (2) the thickness dependent structure change of Fe films from fcc to bcc on Co and Cu surfaces and (3) the relationship between structural and electronic properties of Co thin films on Au(111) and their magnetic anisotropy.