Regensburg 2022 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 23: Magnetic Domain Walls

MA 23.5: Vortrag

Mittwoch, 7. September 2022, 10:30–10:45, H48

Strain-controlled Domain Wall injection into nanowires for sensor applications — •Giovanni Masciocchi^1,2, Mouad Fattouhi³, Andreas Kehlberger², Luis López Díaz³, and Mathias Kläui¹ — ¹Institute of Physics, Johannes Gutenberg University Mainz, 55099 Mainz, Germany — ²Sensitec GmbH, 55130 Mainz, Germany — ³Department of Applied Physics, Universidad de Salamanca, E-37008 Salamanca, Spain

In this study, we address a well-known challenge in magnetic sensor development, which is the effect of packaging-induced strain on the sensor properties. While previously the field operation window has only been studied in idealized operation conditions, in real devices further external factors such as strain play a role.

In this experimental work, we investigate the injection of a 180° domain wall from a nucleation pad into a nanowire, as typically used for domain wall-based sensors, while straining the device along selected directions. Combining our experimental measurements by Kerr microscopy with micromagnetic simulations, we find that strain, regardless of its direction, increases the domain wall injection field due to the magnetoelastic coupling of the magnetic material. The above-described observations can be explained by an effective strain-induced anisotropy in the device.

We find additionally that a careful material preparation, comprising of an annealing step, can reduce the effective anisotropy caused by the strain in the magnetic layer. With this we show that a device free of magnetostrictive behavior can be achieved.