Berlin 2008 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 18: Poster I : Bio Magn. (1-2); Mag.Imgaging (3-9); Magn. Semiconductors (10-16); Half Metals & Oxides (17-20); Coupl.Phenomena (21-27); Magn. Mat. (28-41); Micro & Nanostr. Magn. Materials (42-61); Micro Magn. (62-64); Surface Magnetism (65-70); Transport Phenomena (71-85)
MA 18.41: Poster
Dienstag, 26. Februar 2008, 15:15–18:30, Poster E
Magnetoresistance and magnetization of magnetically ordered proton irradiated graphite — •Jose Barzola-Quiquia1, Martin Rothermel2, Daniel Spemann2, Tilman Butz2, Michael Ziese1, and Pablo Esquinazi1 — 1Division of Superconductivity and Magnetism, University of Leipzig, Leipzig, Germany — 2Division of Nuclear Solid State Physics, University of Leipzig, Leipzig, Germany
Defect induced magnetic order is a new phenomenon in material science that refers to the triggering and manipulation of magnetic order and magnetic moments in nominally non-magnetic materials by lattice defects and/or non-magnetic add atoms. A noticeable example of this effect is the magnetic order produced by proton irradiation of graphite. In this contribution we present SQUID measurements of the magnetization showing a fluence dependent Curie temperature as well as magnetoresistance and Hall effect measurements showing irreversible behavior similar to that found in ferromagnetic films. This indicates the presence of spin/domain reorientation effects in irradiated graphite. The observed magnetoresistance effects and Curie temperatures above room temperature are promising facts that may lead to useful carbon-based devices in the near future.