Regensburg 2016 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 41: Magnetic Coupling Phenomena
MA 41.5: Vortrag
Donnerstag, 10. März 2016, 10:30–10:45, H33
Searching for exchange bias in Heusler alloys — •Rocio Yanes1, Eszter Simon2, Laszlo Szunyogh2, and Ulrich Nowak1 — 1Universität Konstanz, Konstanz, Germany — 2Budapest University of Technology and Economics, Budapest, Hungary
The exchange bias (EB) effect is a unidirectional anisotropy of a magnetic system, related to the coupling between a ferromagnet (FM) and an antiferromagnet (AF). The EB effect is used in multiple magnetic devices to stabilize the magnetization as in GMR sensors, magnetic tunnel junctions etc. This fact has increased the demand of AF and it has led to an increased interest for novel AF materials with Néel temperature above room temperature, being Heusler alloys (HA) promising candidates for that.
In this work we studied the magnetic properties of a series of HA/FM bilayers using a multiscale modeling, linking ab initio calculations with dynamical spin model simulations [1]. This technique provides us a direct knowledge of the exchange interactions at the AF/FM interface.
In order to check the possible existence of EB effect, numerical calculations of the hysteresis loops of: Ni2MnAl(B2)/FM bilayers (FM=Co and Fe) were carried out for different values of the thickness of the AF substrate (tAF). Our preliminary results indicate that for perfect Ni2MnAl/FM bilayers there is no (in-plane) EB effect. However, when chemical disorder is included in the AF layer a small EB appears.
[1] L. Szunyogh et. al, Phys. Rev. B, 83,024401 (2011).