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HL: Fachverband Halbleiterphysik

HL 14: Spintronics: Transport and Theory

HL 14.5: Vortrag

Montag, 7. März 2016, 15:45–16:00, H13

Exchange coupling between soft magnetic materials and hard magnetic Dysprosium layers — •Markus Ehlert, Thomas Hupfauer, Markus Schitko, Günther Bayreuther, and Dieter Weiss — Institute of Experimental and Applied Physics, University of Regensburg, Germany

The control of the magnetic properties of thin ferromagnetic films is crucial for the functionality of spintronic devices, e.g., for the detection of the spin Hall effect [1]. The goal of our work is to improve the magnetic stability of commonly used soft ferromagnets by making use of the exchange coupling between soft and hard magnetic materials. We report on measurements of the magnetic interplay between soft magnetic Fe or Co layers and hard magnetic Dysprosium (Dy) layers. Microstructured thin films of Fe/Dy and Co/Dy multilayers were prepared by electron-beam lithography and ultra-high vacuum sputtering. The magnetic properties of the materials were determined by means of the Anisotropic Magnetoresistance (AMR) effect. By analyzing and comparing the corresponding AMR data we show that the presence of a Dy layer on top of a soft magnetic material significantly influences its magnetic properties. In our experiments we could enhance, e.g., the in-plane coercive field by one order of magnitude. We investigated the exchange coupling in the ferromagnetic (T<90 K) and antiferromagnetic (T>90 K) phase of Dy and also its dependence on the thickness of the soft magnetic material. All experimental results can consistently be explained with the model of the AMR effect.

[1] M. Ehlert et al., Phys. Status Solidi B 251, 1725-1735 (2014).