X-ray magnetic circular dichroism in iron/rare-earth multilayers and the impact of modifications of the rare earth's electronic structure

Magnetischer Röntgendichroismus in Eisen/Seltene Erd-Vielfachschichten und der Einfluß von Veränderungen der elektronischen Struktur der Seltenen Erde

von Markus Münzenberg
Dissertation
Datum der mündl. Prüfung:2000-10-24
Erschienen:2001-02-22
Betreuer:Prof. Dr. Wolfgang Felsch
Gutachter:Prof. Dr. Wolfgang Felsch
Gutachter:PD Dr. Peter Schaaf
Zum Verlinken/Zitieren: http://dx.doi.org/10.53846/goediss-2862

 

 

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Englisch

This work illuminates the possibilities of circular magnetic dichroism in X-ray absorption (XMCD) for the studies of ordered magnetism. The element and electron-shell sensitivity of this spectroscopic method is used to study the magnetic properties of multilayer systems with Fe and Ce, La and Gd as the main constituents. The XMCD spectra at the rare earth (RE) L2,3 edges are analyzed in a phenomenological two-parameter model. It explains the observed shapes of the dichroic signals qualitatively. The first part of the thesis is concerned with the systems Fe/REHx . The main interest is to probe the impact of the metal-to-insulator transition in the REHx sublayers on the spectra. It is produced by increasing the hydrogen content. The second part is devoted to the multilayer system Fe/Ce1-xSix. X-ray absorption spectra at the Ce L and M edges reveal that the degree of localization of the Ce-4f states increases with increasing concentration of the s-p element Si, but the electronic configuration of Ce remains a -phase like. The element selectivity of XMCD is also used to investigate the role of the interfaces in Fe/Ce multilayers in the process of magnetization reversal in an applied magnetic field in the last part.
Keywords: Magnetic multilayers; X-ray magnetic circular dichroism; metal-to-insulator transition; interfacial magnetism
Schlagwörter: Magnetische Vielfachschichten; magnetischer Röntgendichroismus; Metall-Isolator Übergang; magnetische Grenzflächen
 
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