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MA: Fachverband Magnetismus
MA 33: Poster II
MA 33.8: Poster
Friday, March 26, 2010, 11:00–14:00, Poster B1
Hydrogen mediated ferromagnetism in ZnO single crystals — •Khalid Muhammad1, Esquinazi Pablo1, Spemann Daniel2, Anwand Wolfgang3, and Brauer Gerhard3 — 1Division of Superconductivity and Magnetism, University of Leipzig, 04103 Leipzig, Germany — 2Division of Nuclear Solid State Physics, University of Leipzig, 04103 Leipzig, Germany — 3Institut für Ionenstrahlphysik und Materialforschung, Forschungszentrum Dresden-Rossendorf, 01314 Dresden, Germany
We have investigated the magnetic properties of hydrogen (H) plasma treated ZnO single crystals. The H-concentration before and after H-plasma treatment has been determined by using nuclear reaction analysis. The H-concentration after treatment was found ≃ 0.6 at%. The magnetic properties of H-plasma treated ZnO single crystals have been investigated by SQUID magnetometry. Hysteresis loops applying magnetic fields parallel and perpendicular to the plane of the sample were measured at 5 and 300 K for each sample revealing magnetic anisotropy. We have observed a giant enhancement of magnetization in H-plasma treated ZnO samples. The ferromagnetic Curie temperature was found to be above 400 K. The saturation magnetization at 300 K was ∼ 10 emu/g, several orders of magnitude higher than that reported in literature. In order to investigate the penetration of H-ions in the ZnO single crystals we have etched the surface of the samples. We found that most of the sample ferromagnetic moment vanishes after etching the first 20 nm layer in agreement with the expected H-penetration depth.