Regensburg 2007 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 15: Poster:ThinFilms(1-33),Transp.(34-49),ExchBias(50-56),
Spindynamics(57-70),Micro-nanostr.Mat.(71-82),
Particles/Clust.(83-88), Mag.Imag./Surface(89-96),
Spinelectronics(97-109), Theory/Micromag.(110-116),
Spinstruct/Phasetr.(117-128),Magn.Mat.(129-139),
Aniso.+Measuring(140-145), MolMag.(146-152),
MSMA(153-156)
MA 15.72: Poster
Dienstag, 27. März 2007, 15:00–19:00, Poster A
Room temperature magnetic order in proton irradiated graphite: latest results — •Kristian Schindler1, Jose Barzola-Quiquia1, Martin Rothermel2, Annette Setzer1, Pablo Esquinazi1, and Tilman Butz2 — 1Division of Superconductivity and Magnetism, Institute for Experimental Physics II, University of Leipzig, Linnéstr. 5, 04103 Leipzig, Germany — 2Division of Nuclear Solid State Physics, Institute for Experimental Physics II, University of Leipzig, Linnéstrasse 5, 04103 Leipzig, Germany
We discuss recent results concerning the magnetic properties of proton irradiated micro-spots produced on highly oriented pyrolytic graphite (HOPG) samples. A proton microbeam of 2.25MeV energy was used to create micrometer spots on HOPG. We have used specially made sample holders that allow us to irradiate the samples and to measure them in the SQUID without any change in their positions. The SQUID resolution and reproducibility enable the measurement of relative changes in the magnetic moment of the sample of the order of 2 × 10−7 emu. We discuss the influence of parameters like proton current and irradiation under low temperature conditions on the measured magnetic order. We compare and combine the results obtained by SQUID and scanning probe microscopy measurements. The electrostatic and thus material changes at the irradiated area are discussed. We compare our results with recently obtained results of X-rays magnetic circular dichroism (XMCD) measurements (at the carbon K-edge) on irradiated spots in carbon films that support the ferromagnetic order observed in SQUID measurements.