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

本研究的目的是阐明单层磁性薄膜表面磁性的起源。为此，我们用自旋和角分辨光电子能谱研究了固体表面和磁性和非磁性晶体表面上生长的磁性薄膜的电子结构，在本项目期间，我们研究了（1）典型的铁磁表面Ni单晶表面，（2）Co（001）表面Fe薄膜，其已知形成fcc和bcc铁，（3）预期显示膜厚度相关的磁各向异性的Co薄膜，和（4）一些外延生长的磁性薄膜如MnAs、MnSb等。结果，阐明了（1）Ni的自旋相关价带结构和电子相关效应，（2）Fe薄膜在Co和Cu表面由fcc向bcc结构的厚度变化;（3）Co薄膜在Au（111）表面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.