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HL: Fachverband Halbleiterphysik

HL 36: Magnetic Semiconductors (jointly with MA)

HL 36.3: Vortrag

Dienstag, 27. März 2012, 10:00–10:15, H 0112

EuO on Silicon for spintronics investigated by HAXPES — •C. Caspers¹, M. Müller¹, A. Gloskovskii², M. Gorgoi³, C.S. Fadley⁴, and C.M. Schneider^1,5 — ¹Peter Grünberg Institut (PGI-6), Forschungszentrum Jülich — ²Analytische und Anorganische Chemie, Johannes Gutenberg-Universität, Mainz — ³Helmholtz-Zentrum für Materialien und Energie, BESSY II, Berlin — ⁴Department of Physics, University of California Davis, USA — ⁵Fakultät für Physik and Center for Nanointegration Duisburg-Essen

Magnetic oxides combine electrical insulation and spin selectivity, qualifying them as highly efficient spin-selective tunnel barriers on silicon. Our approach joins two beneficial aspects: EuO is predicted to be the only magnetic oxide thermodynamically stable on silicon, the mainstay of semiconductors; moreover we are holding full control over structural, chemical, and magnetic properties of the MBE-grown EuO.

EuO thin films were synthesized by Oxide-MBE. RHEED pattern confirm the epitaxial growth of EuO on clean Si(100). A bulk-sensitive HAXPES study revealed an integral Eu(2+) valency (ferromagnetic) of 4 nm thick EuO/Si heterostructures with less than 4% antiferromagnetic Eu(3+). A depth-dependent HAXPES investigation with optimized interface sensitivity provided the optimum chemical parameters for the EuO/Si transport interface: The formation of EuSix can be minimized to less then 10% coverage of the interface, and SiOx is found to be < 20%. Concluding, we succeeded in preparing EuO/Si heterostructures with high-quality magnetic, structural and chemical properties, being promising as spin filter contacts to silicon.