Ozerov, M.Romhanyi, J.Belesi, M.Berger, H.Ansermet, J. -Ph.Van Den Brink, JeroenWosnitza, J.Zvyagin, S. A.Rousochatzakis, I.2014-11-132014-11-132014-11-13201410.1103/PhysRevLett.113.157205https://infoscience.epfl.ch/handle/20.500.14299/108668WOS:000342797100014The recent discovery of Skyrmions in Cu2OSeO3 has established a new platform to create and manipulate Skyrmionic spin textures. We use high-field electron spin resonance with a terahertz free-electron laser and pulsed magnetic fields up to 64 T to probe and quantify its microscopic spin-spin interactions. In addition to the previously observed long-wavelength Goldstone mode, this technique probes also the high-energy part of the excitation spectrum which is inaccessible by standard low-frequency electron spin resonance. Fitting the behavior of the observed modes in magnetic field to a theoretical framework establishes experimentally that the fundamental magnetic building blocks of this Skyrmionic magnet are rigid, highly entangled and weakly coupled tetrahedra.text::journal::journal article::research article