| AVS 64th International Symposium & Exhibition | |
| Novel Trends in Synchrotron and FEL-Based Analysis Focus Topic | Wednesday Sessions |
| Session SA+AS+HC+SS-WeA |
| Session: | In Situ and Operando Characterization of Interfacial Reactions in Energy & Electronic Devices |
| Presenter: | Jan Vogel, Institut Néel, CNRS/UGA, Grenoble, France |
| Authors: | J.D. Vogel, Institut Néel, CNRS/UGA, Grenoble, France O. Boulle, SPINTEC, CNRS/CEA/UGA, Grenoble, France R. Juge, SPINTEC, CNRS/CEA/UGA, Grenoble, France D.S. Chaves, Institut Néel, CNRS/UGA, Grenoble, France S. Pizzini, Institut Néel, CNRS/UGA, Grenoble, France S.G. Je, SPINTEC, CNRS/CEA/UGA, Grenoble, France G. Gaudin, SPINTEC, CNRS/CEA/UGA, Grenoble, France T.O. Mentes, Elettra-Sincrotrone Trieste, Italy A. Locatelli, Elettra-Sincrotrone Trieste, Italy M.U.J. Foerster, ALBA Synchrotron Light Facility, Spain L. Aballe, ALBA Synchrotron Light Facility, Spain |
| Correspondent: | Click to Email |
Magnetic skyrmions are chiral spin structures with a whirling spin configuration. Their topological properties, small size and sensitivity to small current pulses have opened a new paradigm for the manipulation of magnetization at the nanoscale. Chiral skyrmion were first experimentally observed in bulk materials [1] and in epitaxial ultrathin films [2], under a strong external magnetic field or at low temperature. More recently, it was predicted that they can also be created in thin magnetic films in stacks with structural inversion asymmetry [3]. We have used high lateral resolution PhotoEmission Electron Microscopy combined with X-ray Magnetic Circular Dichroism (XMCD-PEEM) to show that skyrmions with a size around 150 nm can indeed be stabilized at room temperature and without external magnetic field, in nanostructures of Pt/Co/MgO with a Co thickness of 1 nm [4]. The high sensitivity of the technique allows measuring very thin Co layers buried under protecting cover layers. The vectorial information obtained by rotating the sample with respect to the incoming x-ray direction allowed us obtaining information on the 3-dimensional spin structure of the skyrmions, directly showing the chiral spin configuration with left-handed chirality.
We investigated the dependence of the skyrmion size on an applied magnetic field, revealing that already a moderate field of 4 mT can reduce the skyrmion diameter to a size of 70 nm. We also studied the motion of skyrmions in micron-wide strips of Pt/Co/MgO induced by current pulses. The results show that skyrmions can be moved with moderate current pulses with current densities of some 1011 A/m2, leading to velocities of several tens of m/s.
Our measurements show that synchrotron-based magnetic imaging using PEEM is very powerful for studying the static and dynamic properties of skyrmions in ultrathin magnetic films.
[1] X.Z. Yu et al., Nature 465, 901 (2010). [2] N. Romming et al., Science 341, 636 (2013). [3] A. Fert, V. Cros & J. Sampaio, Nature Nanotech. 8, 152 (2013). [4] O. Boulle, J. Vogel et al., Nature Nanotech. 11, 449 (2016).