Dresden 2006 – wissenschaftliches Programm
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MA: Magnetismus
MA 20: Poster: Films(1-36) Transp(37-56) Ex.Bias(57-67) Spindyn(68-80) Micromag(81-95) Particle(96-109) Imag.+Surface(110-113) Spinelectr(114-122) Theory+Micromag(123-131) Spinstr+Aniso(132-142) MagMat(143-156) Meas(157,158) MolMag+Kondo(159-162) Postdead(163-)
MA 20.26: Poster
Dienstag, 28. März 2006, 15:15–19:15, P1
Weak ferromagnetism in epitaxial metastable c-FeSi thin films on MgO(100) — •M. Walterfang1, K. Trounov1, W. Keune1, U. Rücker2, and K. Westerholt3 — 1Angewandte Physik, Universität Duisburg-Essen, 47048 Duisburg — 2Forschungszentrum Jülich, Institut für Festkörperforschung, 52425 Jülich — 3Institut für Experimentalphysik/Festkörperphysik, Ruhr-Universität Bochum, 44780 Bochum
The metastable c-FeSi phase (B2 structure) is an interesting spacer material providing large interlayer exchange coupling [1]. Thin films of nominal composition c-FeSi0.85 were grown by codeposition of 57Fe and Si onto MgO(100) carrying a thin Fe or Cr buffer layer. The metastable B2 structure was observed by XRD and Mössbauer spectroscopy (CEMS). Based on EDX results, CEM spectra have been analyzed in terms of a quadrupole doublet representing stoichiometric c-FeSi, and a magnetic component with a hyperfine field distribution, P(Bhf), representing non-stoichiometric c-FeSix. CEMS and SQUID magnetometry demonstrate magnetic ordering effects upon cooling to 4.2 K. Stoichiometric c-FeSi is observed to be paramagnetic at 300 K and ferromagnetic below ∼ 30 K, while non-stoichiometric c-FeSix is ferromagnetic at and below 300 K. The Fe atomic magnetic moments µFe in the ground state (T → 0 K) are found to be ∼ 0.1 µB for both phases. These small Fe moments are reflected in the observed small values of ⟨Bhf⟩ ≈ 2 - 4 T at low temperature.
Sponsored by DFG (GRK 277 und Ke 273/18-1).
[1] B. Croonenborghs et al., Phys. Rev. B 71, 024410 (2005).