Magnetic Properties of Ultra Thin Epitaxial Fe Films on GaAs (001).

Spangenberg, M. ; Neal, J. R. ; Shen, T. H. ; Morton, S. A. ; Tobin, J. G. ; Waddill, G. D. ; Matthew, J. A. D. ; Greig, D. ; Malins, A. E. R. ; Seddon, E. A. ; Hopkinson, M.

Technical Information Center Oak Ridge Tennessee

关键词: Magnetic properties;    Gallium arsenides;    Thin films;    Ferromagnetic materials;    Molecular beam epitaxy;   

RP-ID  :  DE200415009722

学科分类：工程和技术（综合）

美国|英语

来源: National Technical Reports Library

【 摘 要 】

The magnetic properties of epitaxial Fe films on GaAs in the range of the first few monolayers have been the subject of a considerable number of investigations in recent years. The absence of magnetic signatures at room temperature has been attributed to the existence of a magnetic 'dead' layer as well as superparamagnetism. By examining the temperature dependence of the magnetic linear dichroism of the Fe core level photoelectrons, we found that these 'non-ferromagnetic' layers had in fact a Curie temperature, T(sub c), substantially lower than room temperature, e.g., a T(sub c) of about 240K for thin films of a nominal thickness of 0.9 nm. The values of Curie temperature were sensitive to the initial GaAs substrate conditions and the thickness of the Fe over-layer with a layer of thickness of 1.25 nm showing a T(sub c) above room temperature.