Dresden 2017 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 66: Poster 3

MA 66.7: Poster

Freitag, 24. März 2017, 09:30–13:00, P2-OG2

Giant perpendicular exchange bias with antiferromagnetic MnN — •Philipp Zilske and Markus Meinert — Center for Spinelectronic Materials and Devices, Physics Department, Bielefeld University

Exchange bias systems have been extensively investigated due to their technological applications in magnetic sensors based on magnetic tunnel junctions or spin valves. Recently, a new exchange bias system consisting of MnN/CoFe bilayers, which shows huge in-plane exchange bias up to 1800 Oe at room temperature, was discovered [1].

Here, we report on an out-of-plane exchange bias system that is also based on the antiferromagnet MnN. Ta/MnN/CoFeB/MgO stacks were grown on amorphous SiOx via reactive magnetron sputtering at room temperature. Diffraction measurements revealed a polycrystalline, columnar growth of the MnN in (001) direction. The dependence of the exchange bias field on the MnN and CoFeB thickness, as well as on the annealing temperature was investigated. This way, we achieved perpendicular exchange bias fields up to 3600 Oe with a coercive field around 350 Oe at room temperature. Furthermore, the anisotropy field was determined for the different stacks yielding values up to 3250 Oe. The perpendicular exchange bias reported here is larger than any previously reported value and possibly opens a route to magnetically stable, perpendicularly magnetized spin valves [2].
[1] M. Meinert et al., Phys. Rev. B 92, 144408 (2015)
[2] J. Y. Chen et al., Appl. Phys. Lett. 104, 152405 (2014)