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MA: Fachverband Magnetismus
MA 46: Magnetic Thin Films I
MA 46.13: Talk
Thursday, March 19, 2015, 18:15–18:30, H 1012
Reversible control of magnetism in Fe and FePt/Fe films by voltage induced phase changes — •Kenny Duschek1, 2, Sebastian Fähler1, Heike Schlörb1, Margitta Uhlemann1, and Karin Leistner1 — 1Leibniz Institute for Solid State and Materials Research, Dresden, Germany — 2Hochschule für Technik und Wirtschaft, Dresden, Germany
Voltage control of magnetism in thin films is of key interest for microelectromechanical systems, like sensors or actuators. In FePt and CoPt films, voltage induced faradaic reactions in the native iron oxide layer result in changes in anisotropy and magnetization [1]. As a model system promising even larger magnetization changes we here investigate 2 - 10 nm Fe films charged in 1 M KOH electrolyte. Depending on the applied potential we reversibly reduce the surface layer to Fe or oxidize it to iron oxide. This way we achieve a voltage induced change of saturation magnetization of 23 % for 10 nm, 40 % for 5 nm and 64 % for 2 nm Fe films. Combining this functional Fe layer with an underlying hard magnetic L10-FePt (001) layer, a significant voltage induced change of perpendicular anisotropy is achieved. The results show that electrochemical reactions can be used to tune surface magnetic properties in a large manner, to even switch magnetism on or off or induce a spin reorientation.
[1] K. Leistner, J. Wunderwald, N. Lange, S. Oswald, M. Richter, H. Zhang, L. Schultz, and S. Fähler, Phys. Rev. B 87 (2013) 224411