Regensburg 2016 – scientific programme
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MA: Fachverband Magnetismus
MA 5: Spin Textures and magnetic Phase Transitions
MA 5.4: Talk
Monday, March 7, 2016, 10:45–11:00, H34
Optically probing symmetry breaking in the Skyrmion cuprate Cu2OSeO3 — •Rolf B. Versteeg1, Ignacio Vergara1, Simon Schäfer1, Dario Bischoff1, Aisha Aqeel2, Thomas T.M. Palstra2, Markus Grüninger1, and Paul H.M. van Loosdrecht1 — 1II. Physikalisches Institut - Universität zu Köln, Zülpicher Straße 77, 50937 Cologne, Germany — 2Zernike Institute, Nijenborgh 4, 9747AG Groningen, The Netherlands
Cubic chiral crystal structures provide an ideal platform for the creation and manipulation of topologically protected spin-vortex structures known as Skyrmions. In these materials, the absence of inversion symmetry, the chiral crystal structure, different types of magnetic order, and their coupling to one another give rise to a multitude of linear optical phenomena. These can be used in all-optical methods to access the various magnetic phases as well as the Skyrmion dynamics.
Here, we present a study of the optical properties of the Skyrmion cuprate Cu2OSeO3. Through ellipsometry, we show the existence of dipole-active local crystal-field excitations. Spectroscopic polarimetry is further used to study the different sources of optical rotation present in Cu2OSeO3. The natural optical rotation, originating in the chiral crystal structure, shows the presence of a zero-field magnetoelectric coupling. The magneto-optical activity, quantified by a Verdet coefficient as large as V=-35·103 rad/T·m, allows us to map the magnetic phase diagram, including the Skyrmion lattice phase. Our results show that optical detection of the Skyrmion phase in Cu2OSeO3 is possible and opens new paths in probing of magnetic topological matter.