Berlin 2005 – wissenschaftliches Programm
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MA: Magnetismus
MA 20: Poster:Schichten(1-29),Spintrsp(30-45),Ex-Bias(46-63),Spindyn(64-75),Mikromat.(76-80),Cluster(81-94),Abbv.(95-99),Obflm(100-02),SpElek.(103-09),E-Theo(110-14),Mikromag.(115-16),Spin+PÜ(117-26),Mag.Mat.(127-51),Meth.(152-55),Mol.Mag(156-59),Kondo(160-65
MA 20.109: Poster
Montag, 7. März 2005, 14:00–18:00, Poster TU C
Thin epitaxial films of the Heusler compound Co2Cr0.6Fe0.4Al — •Horst Schneider1, Gerhard Jakob1, Frederick Casper1,2, Andrés Conca1, Martin Jourdan1, Hans-Joachim Elmers1, and Claudia Felser2 — 1Institut für Physik, Universität Mainz, Staudinger Weg 7, 55128 Mainz — 2Institut für Anorganische und Analytische Chemie, Universität Mainz, Düsbergweg 10-14, 55128 Mainz
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Co based Heusler alloys as Co2Cr0.6Fe0.4Al posses a high Curie temperature and according to band structure calculations this material is half metallic, i.e. there exists only one spin direction for the charge carriers at the Fermi edge. We prepared thin epitaxial films of this compound in the B2 structure by sputtering and laser ablation and realized first tunnel magnetoresistive elements. Films grown at high temperatures (T=600 oC) on a-plane (1120) Al2O3 are fully epitaxial with the (110) and (110) planes of the film parallel to the (1120) and (0001) planes of the substrate, respectively. The films show nearly rectangular hysteresis loops with coercitive fields of the order of 10 mT. On GaAs substrates film deposition at lower temperatures and subsequent annealing improved the magnetic moment to 3.5 µB per fourmula unit. Magnetooptical Kerr measurements show an in-plane anisotropy of the magnetization with the easy axis in {001} direction. Hall measurements show a strong anomalous Hall effect and a weak normal Hall voltage signalling the existence of a compensated Fermi surface.