Berlin 2018 – scientific programme

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MA: Fachverband Magnetismus

MA 52: Poster II

MA 52.40: Poster

Thursday, March 15, 2018, 15:00–18:00, Poster C

Skyrmion bubbles generation with oblique magnetic field and electrical currents — Sören Nielsen¹, •Enno Lage¹, Christian Denker², Markus Münzenberg², and Jeffrey McCord¹ — ¹Nanoscale Magnetic Materials - Magnetic Domains, Institute for Materials Science, Universität Kiel, Germany — ²Institut für Physik, Universität Greifswald, Germany

Room temperature magnetic skyrmion bubbles have been found in Ta/CoFeB/TaO_x and similar systems comprising heavy metal/ferromagnet/oxide layers. Ta/CoFeB/MgO is a promising system presumably allowing for successful skyrmion bubble generation and detection by magnetic tunnel junctions (MTJ) with high TMR ratios. In this work, typical MTJ bottom electrodes and barriers (5 nm Ta/x CoFeB/3 nm MgO) trilayers with an optional Ru capping, deposited by e-beam evaporation (MgO, Ru) and magnetron sputtering (Ta, CoFeB), were used for skyrmion generation. We will present our results on skyrmions. Skyrmions are observed by magneto-optically using magneto-optical Kerr effect microscopy. A transition from in-plane to out-of-plane magnetic anisotropy is found for a CoFeB thickness of x ≈ 1.4 nm. The stability of skyrmion bubbles in proximity of the transitional regime was found to cover an increased field range with increasing film thicknesses. Paths for the enhanced generation of skyrmion bubbles in thinner magnetic films based on the application of combined out-of-plane bias fields and in-plane magnetic field pulses will be demonstrated. We will further discuss the interaction of skyrmion bubbles with electrical currents.