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MA: Magnetismus

MA 28: Hauptvortrag Rüdiger

MA 28.1: Hauptvortrag

Freitag, 28. März 2003, 10:15–10:45, HSZ/03

Room temperature spin polarization of epitaxial half-metallic CrO₂(100) and Fe₃O₄(111) films — •U. Rüdiger¹, Y. Dedkov², M. Fonine², C. König², and G. Güntherodt² — ¹Fachbereich für Physik, Universität Konstanz, 78457 Konstanz — ²II. Physikalisches Institut, RWTH Aachen, 52056 Aachen

The intriguing feature of the materials class of half-metallic ferromagnets (HMF) is metallic conductivity for one spin component and insulating behavior for the other one. The theoretically predicted 100% spin polarization (SP) at E_F of HMFs make them promising materials for magnetoeletronic and spintronic devices. The spin-dependent electronic structure of thin epitaxial films of Fe₃O₄(111) and CrO₂(100) has been investigated at room temperature (RT) by means of spin- and energy-resolved photoemission spectroscopy. Epitaxial Fe₃O₄(111) films have been grown on W(110) and Al₂O₃(1120) substrates by oxidizing epitaxial Fe(110) films. These films show near E_F a maximum SP of -(80±5)% at RT [1]. Epitaxial CrO₂(100) films have been deposited on TiO₂(100) substrates by a chemical vapor deposition technique. An extraordinary high SP of about (95±5)% was found at E_F at RT [2].

[1] Yu. S. Dedkov, U. Rüdiger, and G. Güntherodt, Phys. Rev. B 65, 064417 (2002).

[2] Yu. S. Dedkov, M. Fonine, C. König, U. Rüdiger, G. Güntherodt, S. Senz, and D. Hesse, Appl. Phys. Lett. 80, 4181 (2002).