Regensburg 2016 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 17: Poster Session I

MA 17.70: Poster

Dienstag, 8. März 2016, 09:30–12:30, Poster B1

Optimal doping of antiferromagnetic MnN for improved exchange bias — •Mareike Dunz, Björn Büker, and Markus Meinert — Center for Spinelectronic Materials and Devices, Physics Department, Bielefeld University, Germany

In many spinelectronic devices, an exchange bias system is used to pin a ferromagnetic reference layer by coupling it to an antiferromagnetic film. We report on a new polycrystalline exchange bias system consisting of MnN/CoFe bilayers that shows high exchange bias of up to 1800 Oe at room temperature. However, it has a broad blocking temperature distribution with its median around 160 ^∘C and requires larger film thicknesses of the antiferromagnetic MnN compared to other exchange bias systems [1].

To optimize the system, doping of the MnN layer was investigated. Defect energies of elements throughout the periodic table substituting Mn were calculated by density functional theory to find optimal dopants. Exchange bias stacks with doping concentrations of a few percent were prepared by reactive co-sputtering and their magnetic properties were analyzed. Effects of the defect energy, large atomic number, or large atomic radii are discussed.

[1] M. Meinert, B. Büker, D. Graulich, and M. Dunz. Large exchange bias in polycrystalline MnN/CoFe bilayers at room temperature. Phys. Rev. B. 92(14), 144408 (2015).