Dresden 2011 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 32: Magnetic Thin Films I
MA 32.2: Vortrag
Mittwoch, 16. März 2011, 11:15–11:30, HSZ 04
Growth, structure, and magnetic properties of epitaxial NixMn100−x single layers and Co/NixMn100−x bilayers on Cu3Au(100) — •Muhammad Yaqoob Khan1, W. A. A. Macedo2, P. L. Gastelois2, J. Miguel1, M. D. Martins2, and W. Kuch1 — 1Institut für Experimentalphysik, Freie Universität Berlin, 14195 Berlin, Germany — 2Centro de Desenvolvimento da Tecnologia Nuclear, 31270-901 Belo Horizonte, MG, Brazil
In contrast to Cu(100), on which NiMn grows with its c axis in the film plane, the larger lattice constant of Cu3Au(100) should enable growth of ordered antiferromagnetic L10 NiMn epitaxial thin films with the c axis perpendicular to the plane. The growth and structure of single-crystalline ultrathin NixMn100−x films on Cu3Au(100), and also the magnetic properties of Co/NixMn100−x bilayers have been investigated by low-energy electron diffraction (LEED), reflection high-energy electron diffraction (RHEED), and magneto-optical Kerr effect (MOKE). For the concentration range 10 ≤ x ≤ 77, our results reveal good epitaxial layer-by-layer growth at a substrate temperature of 300 K. From LEED-IV and RHEED measurements, the equiatomic NiMn films were found to be in a face-centered tetragonal (fct) structure as expected for the L10 NiMn phase, with the c axis along the film normal. For Co/NiMn bilayers with 23 ≤ x ≤ 55, MOKE hysteresis loops show a thickness-independent coercivity, suggesting no magnetic coupling at the interface and hence no indication of antiferromagnetism in the NiMn in contrast to earlier observations on Co/Ni50Mn50/Cu(100).