Dresden 2017 – scientific programme

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MA: Fachverband Magnetismus

MA 41: Micromagnetism / Computational Magnetics

MA 41.10: Talk

Wednesday, March 22, 2017, 17:30–17:45, HSZ 101

Inverse magnetostrictive stress sensors based on CoFeB/MgO/CoFeB tunnel junctions — •Niklas Dohmeier¹, Günter Reiss¹, Karsten Rott¹, Ali Tavassolizadeh², and Dirk Meyners² — ¹Center for Spinelectronic Materials and Devices, Physics Department, Bielefeld University, Germany — ²Institute for Materials Science, Christian-Albrechts-Universität zu Kiel

We investigate double-pinned CoFeB/MgO/CoFeB tunnel junctions as sensors for mechanical stress.
Applying stress on a magnetic material induces an anisotropy. Depending on the material and direction of the stress, the anisotropy can be parallel or perpendicular to the stress direction. This effect can be utilized in TMR stacks to detect mechanical stress via changes in the tunnel resistance.
A standard TMR stack with a pinned and a free magnetic layer needs a magnetic bias field to set the optimum working condition. We are aiming for a replacement of the external bias field.
TMR stacks have been realized with MnIr-based pinning of both electrodes. By choosing different MnIr thicknesses, different blocking temperatures were accomplished. Through a series of field cooling processes with increasing temperatures the optimum temperature was found for crossed ground state magnetizations of the electrodes.
On these systems TMR measurements and bending experiments have been performed in order to show the performance of non-collinear pinned TMR stacks as stress sensors with the possibility of differentiating tensile and compressive stress.