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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 20.17: Poster

Dienstag, 28. März 2006, 15:15–19:15, P1

Epitaxial thin films of Co₂Cr_0.6Fe_0.4Al — •Andres Conca, Martin Jourdan, Anna Gerken, Christian Herbort, and Hermann Adrian — Institut für Physik, Johannes Gutenberg Universität, Staudinger Weg 7, 55128 Mainz, Germany

The full Heusler compound Co₂Cr_0.6Fe_0.4Al (CCFA) is expected to show half-metallicity, i.e. 100 % spin polarization at E_F. We were able to deposite high quality CCFA thin films. The films were deposited by magnetron dc sputtering in a chamber with a base pressure ≈ 10⁻⁸mbar. A comparison of films deposited on different buffer layers at different temperatures is shown. The crystalline order was studied by X-ray diffraction. We observed that the films grow in the B2 structure. The preference of CCFA films to grow in the B2 structure instead of the fully ordered structure L2₁ is well known. This implies a complete mixing of Cr, Fe and Al atoms. The magnetic properties were determined with a VSM magnetometer, the relation between volume magnetization and crystalline quality of the samples is discussed. In order to implement CCFA films in spintronic devices such as MTJ’s, the surface quality of the films is of critical importance. Therefore, the surface order was characterized by RHEED and the topology by STM/AFM. The dependence of surface roughness and ordering on the deposition temperature for the different buffer layers is discussed.