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MA: Fachverband Magnetismus
MA 9: Spin Excitations/Spin Torque
MA 9.6: Talk
Monday, March 16, 2015, 16:45–17:00, H 0112
Interfacial Dzyaloshinskii-Moriya interaction in Ta\CoFeB\MgO nanowires — •R. Lo Conte1,2, E. Martinez3, A. Hrabec4, A. Lamperti5, T. Schulz1, L. Nasi6, L. Lazzarini6, B. Ocker7, C. H. Marrows4, T. A. Moore4, and M. Kläui1,2 — 1Johannes Gutenberg Universität-Mainz, Mainz, Germany — 2Graduate School of Excellence Materials Science in Mainz, Mainz, Germany — 3Universidad de Salamanca, Salamanca, Spain — 4University of Leeds, Leeds LS2 9JT, U.K. — 5Laboratorio MDM, IMM-CNR, Agrate Brianza, Italy — 6IMEM-CNR, Parma, Italy — 7Singulus Technologies, Kahl am Main, Germany
We use domain wall motion due to spin orbit torques to quantify the Dzyaloshinskii-Moriya interaction (DMI) at the Ta\CoFeB interface in out-of-plane magnetized nanostructures with structural inversion asymmetry [1]. Current-induced domain wall motion (CIDWM) experiments were carried out in Ta\Co20Fe60B20\MgO nanowires and the DW motion is imaged by differential Kerr microscopy technique. We find that the velocity of the DW is strongly affected by the presence of a longitudinal magnetic field, resulting in a different velocity for the up-down and down-up domain walls at fixed current density and magnetic field. Such results are interpreted by the spin-Hall effect-torque model, where the chirality of the domain walls is fixed by the DMI at the [heavy metal]\ferromagnet interface. The DMI is found to depend on the B diffusion to the Ta interface, which is a consequence of the annealing process used to obtain the desired perpendicular magnetic anisotropy. [1] R. Lo Conte et al., arXiv: 1409.3753 (2014).