Dresden 2011 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 55: Surface magnetism II (jointly with MA)

O 55.2: Vortrag

Mittwoch, 16. März 2011, 15:15–15:30, CHE 184

Magnetic and structural investigations of thin ferromagnetic CrSb layers on GaAs(110)/GaAs(001) — •Carsten Godde and Ulrich Köhler — Institut für Experimentalphysik IV / AG Oberflächen, Ruhr-Universität Bochum, Germany

In this contribution we present structural and magnetic measurements of thin CrSb layers on GaAs(110) and GaAs(001) surfaces. These systems are of great interest because of their possible use as spin aligner for spin injection in semiconductors. Thin CrSb layers up to 4 ML thickness grow in the metastable zinc blende structure on GaAs and keep ferromagnetic properties and structural stability up to high annealing temperatures which is interesting for enabling better crystalline quality. We investigate the growth of CrSb on the GaAs surfaces at different coverages and annealing temperatures by STM, LEED and SQUID magnetometry. The CrSb films are co-deposited on the GaAs substrate by MBE at a deposition temperature of 250^∘C with a co-deposition ratio of Cr and Sb: 1:6. On the GaAs(110) surface STM shows for a 3ML CrSb deposition a closed film of rectangular and rooflike islands elongated in [110]-direction of substrate with increasing tendency towards a flat continuous morphology with height variations in the monolayer range after thermal processing at 300^∘C for 45min. These flat areas are characterized by a atomic fishbone row structure in [110]-direction. SQUID magnetometry measurements show ferromagnetic characteristics of the thin CrSb layers with a magnetic moment per atom of ≈ 3 µ_B.