title: Filming the formation and fluctuation of skyrmion domains by cryo-Lorentz transmission electron microscopy.
abstract: Magnetic skyrmions are promising candidates as information carriers in logic or storage devices thanks to their robustness, guaranteed by the topological protection, and their nanometric size. Currently, little is known about the influence of parameters such as disorder, defects, or external stimuli on the long-range spatial distribution and temporal evolution of the skyrmion lattice. Here, using a large (7.3 × 7.3 μm(2)) single-crystal nanoslice (150 nm thick) of Cu2OSeO3, we image up to 70,000 skyrmions by means of cryo-Lorentz transmission electron microscopy as a function of the applied magnetic field. The emergence of the skyrmion lattice from the helimagnetic phase is monitored, revealing the existence of a glassy skyrmion phase at the phase transition field, where patches of an octagonally distorted skyrmion lattice are also discovered. In the skyrmion phase, dislocations are shown to cause the emergence and switching between domains with different lattice orientations, and the temporal fluctuation of these domains is filmed. These results demonstrate the importance of direct-space and real-time imaging of skyrmion domains for addressing both their long-range topology and stability.
authors.affiliation: Laboratory for Ultrafast Microscopy and Electron Scattering, Institute of Condensed Matter Physics, Lausanne Center for Ultrafast Science (LACUS), École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland;
authors.forename: Jayaraman
authors.initials: J
authors.lastname: Rajeswari
authors.affiliation: Laboratory for Quantum Magnetism, Institute of Condensed Matter Physics, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland;
authors.forename: Ping
authors.initials: P
authors.lastname: Huang
authors.affiliation: Laboratory for Ultrafast Microscopy and Electron Scattering, Institute of Condensed Matter Physics, Lausanne Center for Ultrafast Science (LACUS), École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland;
authors.forename: Giulia Fulvia
authors.initials: GF
authors.lastname: Mancini
authors.affiliation: Laboratory for Ultrafast Microscopy and Electron Scattering, Institute of Condensed Matter Physics, Lausanne Center for Ultrafast Science (LACUS), École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland;
authors.forename: Yoshie
authors.initials: Y
authors.lastname: Murooka
authors.affiliation: Physics Department, University of Zurich, CH-8057 Zürich, Switzerland;
authors.forename: Tatiana
authors.initials: T
authors.lastname: Latychevskaia
authors.affiliation: Scottish Universities Physics Alliance, School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom;
authors.forename: Damien
authors.initials: D
authors.lastname: McGrouther
authors.affiliation: Centre Interdisciplinaire de Microscopie Electronique, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland;
authors.forename: Marco
authors.initials: M
authors.lastname: Cantoni
authors.affiliation: Laboratory for Ultrafast Microscopy and Electron Scattering, Institute of Condensed Matter Physics, Lausanne Center for Ultrafast Science (LACUS), École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland;
authors.forename: Edoardo
authors.initials: E
authors.lastname: Baldini
authors.affiliation: Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institut, CH-5232 Villigen, Switzerland;
authors.forename: Jonathan Stuart
authors.initials: JS
authors.lastname: White
authors.affiliation: Competence in Research of Electronically Advanced Materials, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland;
authors.forename: Arnaud
authors.initials: A
authors.lastname: Magrez
authors.affiliation: Department of Quantum Matter Physics, University of Geneva, CH-1211 Geneva, Switzerland.
authors.forename: Thierry
authors.initials: T
authors.lastname: Giamarchi
authors.affiliation: Laboratory for Quantum Magnetism, Institute of Condensed Matter Physics, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland;
authors.forename: Henrik Moodysson
authors.identifier: http://orcid.org/0000-0002-8832-8865
authors.initials: HM
authors.lastname: Rønnow
authors.affiliation: Laboratory for Ultrafast Microscopy and Electron Scattering, Institute of Condensed Matter Physics, Lausanne Center for Ultrafast Science (LACUS), École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland; fabrizio.carbone@epfl.ch.
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Carbone
keywords: Lorentz transmission electron microscopy; magnetic materials; skyrmion dynamics; skyrmions; strongly correlated systems