Berlin 2008 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 11: Spindependent Transportphenomena II
MA 11.6: Vortrag
Montag, 25. Februar 2008, 16:30–16:45, H 0112
Anomalous Hall effect in epitaxial magnetite thin films — •Andrea Boger, Wolfgang Kaiser, Matthias Opel, Sebastian T. B. Goennenwein, and Rudolf Gross — Walther-Meissner-Institut, BayerischeAkademie der Wissenschaften, 85748 Garching, Germany
The ferrimagnet Fe3O4 is an attractive candidate for spintronic devices due to its Curie temperature of about 860 K, and a high spin polarization of P ≤ −(55±10)% [1]. Although magnetite is already in the focus of research for decades, the anomalous Hall effect of epitaxial thin films, in particular the dependence of the transverse conductivity σxy on the longitudinal conductivity σxx, has not yet been studied in detail.
We have grown epitaxial Fe3O4 thin films in three different crystalline orientations by pulsed laser deposition. X-ray diffractometry proves the high crystalline quality of the films, demonstrated by a FWHM of the rocking curves of the (004), (440) and (222)-reflection of only 0.04∘ for (001), (110) and (111) orientation, respectively. Electrical transport measurements were performed at temperatures between 90 K and 375 K at magnetic fields up to 14 T. We have found that σxy is proportional to σxxβ with β ≃ 1.6 for (001) and (111) orientation. In contrast, (110) oriented samples show a change, likely due to the Verwey transition [2], from β = 1.5 below 120 K to β = 1.8 above.
[1] M. Fonin et al., Phys. Rev. B 72, 104436 (2005)
[2] E. J. W. Verwey, Nature 144, 327-328 (1939)
This work is supported by the DFG via priority program 1157.