Dresden 2006 – scientific programme

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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 20.18: Poster

Tuesday, March 28, 2006, 15:15–19:15, P1

Spin-resolved photoemission studies of Co₂Cr_1−xFe_xAl and Co₂FeSi Heusler alloy films — •Jan-Peter Wüstenberg, Marina Sánchez Albaneda, Mirko Cinchetti, Oleksiy Andreyev, Michael Bauer, and Martin Aeschlimann — University of Kaiserslautern, Physics Department, Erwin Schroedinger-Str. 46, 67663 Kaiserslautern, Germany

Heusler alloys represent nowadays a class of materials with a high potential for application in the growing field of spintronics. This is due to the fact that theoretical calculations have predicted for many of such alloys the property of possessing 100% spin polarization at the Fermi level. However, for spintronics applications, the spin polarization must be high not only in the bulk, but also at the surface region. This is not straightforward, since extrinsic as well as intrinsic mechanisms can reduce the surface spin polarization. We have studied thin films of the Heusler compounds Co₂Cr_1−xFe_xAl and Co₂FeSi with spin-resolved photoemission spectroscopy, using as excitation source the second and fourth harmonic of a femtosecond Ti:sapphire laser, with photon energies of 3.1 eV and 6 eV. We compare the dependence of the measured surface spin polarization on the preparation procedure, the sample temperature and the photoemission mechanism, and discuss the observed differences.