Berlin 2018 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 8: Focus Session: Magnetic structurally and compositionally modulated nanowires and nanotubes

MA 8.5: Hauptvortrag

Montag, 12. März 2018, 17:00–17:30, H 1012

Magnetic hardening of nanowires by sandwiching with antiferromagets — •Ulf Wiedwald — Faculty of Physics and Center for Nanointegration Duisburg-Essen, University of Duisburg-Essen, Germany — National University of Science and Technology MISIS, Moscow, 119049, Russian Federation

The growth of magnetic nanowires (NWs) in anodic aluminum oxide (AAO) is a nowadays well-established technique [1]. Such NWs have been suggested as rare earth-free permanent magnets or magneto-electric logic devices [2]. Exploiting the shape anisotropy of 3d-metal NWs at aspect ratios of several hundred in principle yields in a huge magnetic energy product. However, due to vortex formation at the tips and dipolar coupling of neighboring wires it is significantly reduced.

Interfacing the tips with antiferromagnet layers is suitable to overcome such limitations as recently shown by oxidation [2]. We explore the magnetic hardening of FeCo NWs at 300 K by coating their tips with antiferromagnetic FeMn. For this purpose, free-standing tips of micron-long NWs with a diameter of 40 nm are isolated from the AAO membranes and covered with few nm FeMn. In the resulting sandwich structure, the energy product doubles at 300 K due to suppression of vortices [3]. Financial support of the Ministry of Education and Science of the Russian Federation, Increase Competitiveness Program of NUST MISiS K3-2017-022 is gratefully acknowledged.

[1] K. Nielsch et al., Appl. Phys. Lett. 79, 1360 (2001). [2] S. Liébana-Viñas et al., Nanotechnol. 26, 415704 (2015). [3] FZ. Wang et al. Nanotechnol. 28, 29 (2017).