Regensburg 2000 – wissenschaftliches Programm
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AM: Magnetismus
AM 19: Spektroskopie I
AM 19.5: Vortrag
Donnerstag, 30. März 2000, 10:45–11:00, H22
X-ray Magneto-Optics in Lanthanides — •Kai Starke1, Franziskus Heigl1, Antje Vollmer1, Günter Kaindl1, Markus Weiss2, and Gerd Reichardt2 — 1Fachbereich Physik, Freie Universität Berlin — 2BESSY Berlin
Magnetic data storage requires a reversal of local magnetisation in thin films. Besides iron-like metals, they contain various lanthanide (Ln) elements in order to reach a high stability against external magnetic fields. Today, the magnetisation reversal process is mostly analysed by magneto-optical effects; yet it is extremely difficult to obtain reliable element-specific information in this way, because the involved optical transitions are between delocalised valence-electron bands. Here we report the observation of a huge magneto-optical (MO) response in electric dipole transitions between 4d and 4f core levels of Ln elements. We demonstrate that the use of transitions between localised levels has several advantages: (i) the probing soft x-rays can be tuned to 4d – 4f transition energies of individual Ln elements and thus monitor their magnetisation reversal in a compound independently; (ii) MO signals are not affected by thermal changes of optical constants; (iii) lanthanide 4d – 4f transitions are among the strongest in the periodic table so that an x-ray probing depths of about 1 nm can be achieved; this is compatible with the dimensions of coming magneto-electronic devices.