Berlin 2008 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
MA: Fachverband Magnetismus
MA 5: Spindependent Transportphenomena I
MA 5.4: Vortrag
Montag, 25. Februar 2008, 11:00–11:15, H 0112
Ballistic and Diffusive Current Spin Polarization in L1o-ordered FePt and FePd — •Klaus M Seemann1, Vincent Baltz1, Mark C Hickey1, Maureen MacKenzie2, Jorge Miguel3, Florian Kronast4, Wolfgang Kuch3, John N Chapman2, Christopher H Marrows1, and Bryan J Hickey1 — 1E.C. Stoner Laboratory, School of Physics and Astronomy, University of Leeds, Leeds, United Kingdom — 2Department of Physics and Astronomy, University of Glasgow, Glasgow, United Kingdom — 3Institut für Experimentalphysik, Freie Universität Berlin, Berlin, Germany — 4BESSY, Albert-Einstein-Strasse 15, Berlin, Germany
We report on the discrepancy of the current spin polarization in the ballistic and diffusive electron transport regime in L1o-ordered epitaxial FePt and FePd layers. The films studied displayed a chemical long range order parameter of 0.4<S<0.9 and a very strong perpendicular magnetic anisotropy. XMCD-PEEM results confirm the magnetic domain structure that we obtain from simulations employing the Landau-Lifshitz-Gilbert equation very well. By evaluating the spin current conductivity asymmetry based on the Levy-Zhang spin mistracking model we are able to assess the diffusive spin current polarization to be 80-90% [1]. On the other hand, to study the ballistic transport regime we have performed point-contact Andreev-reflection measurements at 4.2K. We obtained a value for the ballistic current spin polarization of 50%.
[1] K.M. Seemann, V. Baltz, M. MacKenzie, J.N. Chapman, B.J. Hickey, and C.H. Marrows, Phys. Rev. B at press, arXiv:0707.2943