Regensburg 2004 – wissenschaftliches Programm
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MA: Magnetismus
MA 13: Poster:Schichten(1-23),Spinabh.Trsp(24-41),Exch.Bias(42-56),Spindyn.(57-67),Mikromag.(68-76),Partikel(77-90),Spinelektr.(91-97),Elektr.Theo.(98-99),Mikromag+PhasÜ+Aniso.(100-105),Magn.Mat.(106-118),Messmethod.(119-121),Obflm.+Abbverf.(122-123)
MA 13.106: Poster
Dienstag, 9. März 2004, 15:00–19:00, Bereich A
Magnetic properties of multiwall carbon nanotubes — •Roland Höhne1, Pablo Esquinazi1, and Teresa Martínez2 — 1Abteilung Supraleitung und Magnetismus, Universität Leipzig, Linnestrasse 5, D-04103 Leipzig — 2Instituto de Carboquimica, CSIC, Miguel Luesma Castan 4, 50015-Zaragoza, Spain
The magnetization of carbon nanotubes composed of a few strands of multiwalled tube were measured with a SQUID magnetometer. The used preparation method allows us to obtain samples without ferromagnetic impurities. The magnetization of the samples shows a diamagnetic behavior at 4 K ≤ T ≤ 300 K without any paramagnetic upturn at low temperatures. After substracting the linear diamagnetic response, the field dependence of the magnetization shows hysteresis with a remanence Mrem ≃ 6 × 10−4emu/g at 5 K. The hysteresis curves however do not show the usual ferromagnetic behavior but apparently the superposition of additional effects. Samples heat treated in hydrogen (45 bar at 350 C for 2 hours) show no appreciable difference. The hysteresis has been measured with the SQUID using two different measuring modes.