Dresden 2011 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 19: Poster I (Bio- and Molecular Magnetism/ Magnetic Particles and Clusters/ Micro- and Nanostructured Magnetic Materials/ Magnetic Materials/ Multiferroics/ Magnetic Shape Memory Alloys/ Electron Theory of Magntism/ Spincaloric Transport/ Magnetic Coupling and Exchange Bias/ Magnetization Dynamics/ Micromagnetism and Computational Magnetics)
MA 19.33: Poster
Dienstag, 15. März 2011, 10:45–13:00, P2
Magnetisation reversal of individual α-Fe nanowires embeded in carbon nanotubes studied by submicron Hall magnetometry — •Kamil Lipert1,2, Stefan Bahr1, Franziska Wolny1, Paola Atkinson1, Uhland Weissker1, Thomas Mühl1, Oliver G. Schmidt1, Bernd Büchner1, and Rüdiger Klingeler2 — 1Leibniz Institute for Solid State and Materials Research IFW, 01069 Dresden, Germany — 2Kirchhoff Institute for Physics, INF 227, D-69120 Heidelberg, Germany
We present the fabrication and characterization of a submicron Hall magnetometer which is based on a n-doped GaAs/AlGaAs heterostructure forming a two dimensional electron gas (2DEG). The device is designed for investigating the magnetic properties of individual nanomagnets. Here, we have studied the magnetisation switching and its dependence on temperature (6K<T<70K) and angle between applied magnetic field and tube axis for two single crystalline Fe nanowires with different diameters d1=26 nm and d2=17 nm coated with carbon shells. For the thicker Fe-nanowire, the data imply a noncoherent character of the magnetisation reversal. In contrast, for the wire with d2=17 nm the nucleation fields increase for fields parallel to the wires axis. This observation resembles the Stoner-Wohlfarth model for rotation of magnetisation in unison, even though the nanowire diameter exceeds the critical diameter of coherent rotation (d0=12 nm). In both cases, the temperature dependence of nucleation fields implies that magnetisation switching is a localized process which in case 1 is initiated by curling.