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 15.101: Poster
Dienstag, 27. März 2007, 15:00–19:00, Poster A
Growth and properties of Fe3O4(111) thin films on ZnO* — •Andrea Boger1, Jürgen Simon2, Andreas Brandlmaier1, Matthias Opel1, Sebastian T. B. Goennenwein1, Werner Mader2, and Rudolf Gross1 — 1Walther-Meissner-Institut der BayerischenAkademie der Wissenschaften, 85748 Garching — 2Institut für Anorganische Chemie der Universität Bonn, 53117 Bonn
Fe3O4, a ferrimagnet with a Curie temperature of about 860 K, is an attractive candidate for direct spin injection into a semiconductor. Compared to metallic 3-d ferromagnets, its electrical conductivity is lower, which reduces conductivity mismatch issues [1]. Furthermore, a high spin polarization of P = −(80±5) % and P = −(55±10)% has been measured for (111) and (001) oriented Fe3O4 surfaces, respectively [2]. Therefore (111)-oriented films are desirable for spin injection.
We have grown 30 nm thick Fe3O4 films on ZnO(0001) substrates by pulsed laser deposition. X-ray diffractometry shows, that the films are relaxed and grow (111)-oriented (Fe3O4(110) ∥ ZnO(2110)) with high crystalline quality, as demonstrated by a FWHM of the rocking curves of the Fe3O4(222) reflection of only 0.02∘. High-resolution TEM proves homogeneous growth and good interface quality. SQUID magnetometry reveals ferromagnetic behavior with a saturation magnetization of 3.2 µB/f.u. at 300 K, about 80 % of the theoretical value. Epitaxial Fe3O4 electrodes thus appear promising for spin injection into ZnO.
[1] G. Schmidt et al., Phys. Rev. B 62, R4790 (2000)
[2] M. Fonin et al., Phys. Rev. B 72, 104436 (2005)
* This work is supported by the DFG via SPP 1157.