Séminaire MCBT : mercredi 23 novembre 2022 à 11h00
Estéfani Marchiori (University of Basel)
Titre : Real–space imaging of magnetic phases in a chiral magnet
Institut Néel, Salle K223
Résumé : The chiral magnet Cu2OSeO3is a ferroelectric material that exhibits a variety of interesting magneticphases, including two distinct topological skyrmion spin textures. Skyrmion phases exist at relatively high temperatures of tens of Kelvin because they require thermal fluctuations to become thermodynamically stable in bulk materials. Recently, small–angle neutron scattering measurements (SANS) revealed a second low–temperature skyrmion phase in Cu2OSeO3[1,2]. Distinct from the well–known high–temperature phase, this low–temperature phase is highly hysteretic and believed to be stabilized by cubic anisotropy. To understand the mixed magnetic phases and the new skyrmion phase in Cu2OSeO3, we performed magnetic imaging of a bulk single crystal using scanning SQUID–on–tip microscopy with sub–100–nm spatial resolution [3]. In this talk, I shalldiscuss the disordered low– temperature skyrmion phase, domain formation, and helimagnetic phases observed.
