Dresden 2014 – scientific programme

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KR: Fachgruppe Kristallographie

KR 4: Multiferroics I (MA jointly with DF, DS, KR, TT)

KR 4.12: Talk

Tuesday, April 1, 2014, 12:30–12:45, BEY 118

Multiferroicity in Cu₂OSeO₃? — •Eugen Ruff¹, Stephan Krohns¹, Helmuth Berger², Peter Lunkenheimer¹, and Alois Loidl¹ — ¹Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg — ²Institute of Physics of Complex Matter, École Polytechnique Fédérale de Lausanne

Skyrmions are topologically stable vortex-like objects, for the first time detected in the B20 alloy MnSi [1]. Their electrical controllability via small currents qualifies skyrmions for applications in high-density magnetic storage devices. The recent discovery of magnetoelectric skyrmions in the insulating chiral magnet Cu₂OSeO₃ leads to another promising route to electrical control [2]. This system is suggested to carry a local electrical dipole, which implies that the skyrmions should be controllable by an external electrical field without losses due to Joule heating. Here we provide a thorough analysis of the magnetic and polar phases of this material, using SQUID and pyrocurrent measurements. In order to investigate the possible ferroelectric properties of Cu₂OSeO₃, we have performed dielectric spectroscopy in various magnetic fields in a broad frequency range below 70 K. Combining all these different techniques, we address the question whether Cu₂OSeO₃ is magnetoelectric or multiferroic. [1] S.Mühlbauer et al., Science 323, 915 (2009). [2] S.Seki et al., Science 336, 198 (2012).