SKM 2021 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 15: Posters Magnetism IV
MA 15.43: Poster
Donnerstag, 30. September 2021, 13:30–16:30, P
Voltage control of perpendicular exchange bias — •Jonas Zehner1,2, Daniel Wolf2, Mantao Huang3, Usama M. Hasan3, David Bono3, Kornelius Nielsch2, Karin Leistner1, and Geoffrey S. D. Beach3 — 1TU Chemnitz — 2IFW Dresden — 3MIT Cambridge
Ferromagnetic layers adjacent to an antiferromagnetic layer give rise to the exchange bias effect which is the basis for a variety of magnetic field sensors or magnetophoretic devices. Controlling exchange bias systems by voltage rather than by electrical current is highly desired for low power magnetic devices. So far, voltage control of exchange bias was mainly reported for systems with an in-plane unidirectional anisotropy below room temperatures. In this abstract, we present the voltage control of a NiO/Pd/Co system exhibiting perpendicular exchange bias system at room temperature. We show that the presence of a Pd interlayer (0.2 nm) is crucial for achieving perpendicular magnetic anisotropy (PMA), and thus also perpendicular exchange bias, in our system. We apply a hydrogen gating mechanism to reversibly switch between PMA and in-plane magnetic anisotropy, and thus to switch on and off perpendicular exchange bias. The observed correlation between an increased coercivity and a decreased exchange bias in the first cycle is explained with a crystallization process of the initially amorphous ferromagnetic layer. The hydrogen gating effect is further transferred to an exchange biased ferrimagnetic (GdCo) system in which we achieve a sign change of the exchange bias due to a hydrogen induced shift of the Curié temperature.