Regensburg 2019 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 15: Magnetism Poster A
MA 15.76: Poster
Dienstag, 2. April 2019, 10:00–13:00, Poster E
Influence of defects inside the (NixMn1−x) antiferromagnetic layer on exchange bias in NixMn1−x/Co bilayers — •Tauqir Tauqir1, M. Yaqoob Khan2, Ismet Gelen1, Ivar Kumberg1, Yasser A. Shokr1, Evangelos Golias1, and Wolfgang Kuch1 — 1Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany — 2Kohat University of Science and Technology, Kohat 26000, Khyber Pakhtunkhwa, Pakistan
A series of experiments are carried out to identify the fundamental mechanism leading to the exchange bias effect in ultrathin epitaxial ferromagnetic/antiferromagnetic (FM/AFM) Co/NixMn1−x ( x=0; 0.25; 0.35; 0.5) bilayer samples on a Cu3Au(001) substrate. Structural or chemical defects are deliberately introduced by Ar+ ion bombardment for short times at a certain depth of the AFM layer. The approach is to influence the pinning sites inside the AFM material by the controlled insertion of disorder. Comparison of the magnetic properties measured by magneto-optical Kerr effect then allows a precise determination of the influence of the Ar+ ion bombardment of the AFM layer. We find that for each sample, defects result in an increase of coercivity and exchange bias field ( Heb). We interpret this by the formation of domains within the AFM layer by the defects, which in turn give rise to uncompensated pinned moments that are responsible for the increased Heb as predicted in the domain-state model.