title: Thermodynamic phase transitions in a frustrated magnetic metamaterial.
abstract: Materials with interacting magnetic degrees of freedom display a rich variety of magnetic behaviour that can lead to novel collective equilibrium and out-of-equilibrium phenomena. In equilibrium, thermodynamic phases appear with the associated phase transitions providing a characteristic signature of the underlying collective behaviour. Here we create a thermally active artificial kagome spin ice that is made up of a large array of dipolar interacting nanomagnets and undergoes phase transitions predicted by microscopic theory. We use low energy muon spectroscopy to probe the dynamic behaviour of the interacting nanomagnets and observe peaks in the muon relaxation rate that can be identified with the critical temperatures of the predicted phase transitions. This provides experimental evidence that a frustrated magnetic metamaterial can be engineered to admit thermodynamic phases.
authors.affiliation: Laboratory for Mesoscopic Systems, Department of Materials, ETH Zurich, 8093 Zurich, Switzerland.|Laboratory for Micro- and Nanotechnology, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland.|Laboratory for Neutron Scattering, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland.
authors.forename: L
authors.initials: L
authors.lastname: Anghinolfi
authors.affiliation: Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland.
authors.forename: H
authors.initials: H
authors.lastname: Luetkens
authors.affiliation: Laboratory for Mesoscopic Systems, Department of Materials, ETH Zurich, 8093 Zurich, Switzerland.|Laboratory for Micro- and Nanotechnology, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland.|Sorbonne Universités, UPMC Univ Paris 06, UMR 7614, LCPMR, 75005 Paris, France.|CNRS, UMR 7614, LCPMR, 75005 Paris, France.
authors.forename: J
authors.initials: J
authors.lastname: Perron
authors.affiliation: School of Physics and Astronomy, SUPA, University of St. Andrews, St. Andrews KY16 9SS, UK.
authors.forename: M G
authors.initials: MG
authors.lastname: Flokstra
authors.affiliation: Laboratory for Mesoscopic Systems, Department of Materials, ETH Zurich, 8093 Zurich, Switzerland.|Laboratory for Micro- and Nanotechnology, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland.
authors.forename: O
authors.initials: O
authors.lastname: Sendetskyi
authors.affiliation: Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland.
authors.forename: A
authors.initials: A
authors.lastname: Suter
authors.affiliation: Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland.
authors.forename: T
authors.identifier: http://orcid.org/0000-0002-7643-4695
authors.initials: T
authors.lastname: Prokscha
authors.affiliation: Condensed Matter Theory Group, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland.
authors.forename: P M
authors.initials: PM
authors.lastname: Derlet
authors.affiliation: School of Physics and Astronomy, SUPA, University of St. Andrews, St. Andrews KY16 9SS, UK.
authors.forename: S L
authors.initials: SL
authors.lastname: Lee
authors.affiliation: Laboratory for Mesoscopic Systems, Department of Materials, ETH Zurich, 8093 Zurich, Switzerland.|Laboratory for Micro- and Nanotechnology, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland.
authors.forename: L J
authors.initials: LJ
authors.lastname: Heyderman