title: A classification of spin frustration in molecular magnets from a physical study of large odd-numbered-metal, odd electron rings.
abstract: The term "frustration" in the context of magnetism was originally used by P. W. Anderson and quickly adopted for application to the description of spin glasses and later to very special lattice types, such as the kagomé. The original use of the term was to describe systems with competing antiferromagnetic interactions and is important in current condensed matter physics in areas such as the description of emergent magnetic monopoles in spin ice. Within molecular magnetism, at least two very different definitions of frustration are used. Here we report the synthesis and characterization of unusual nine-metal rings, using magnetic measurements and inelastic neutron scattering, supported by density functional theory calculations. These compounds show different electronic/magnetic structures caused by frustration, and the findings lead us to propose a classification for frustration within molecular magnets that encompasses and clarifies all previous definitions.
authors.affiliation: School of Chemistry and Photon Science Institute,  The University of Manchester, Manchester M13 9PL,  United Kingdom.
authors.forename: Michael L
authors.initials: ML
authors.lastname: Baker
authors.forename: Grigore A
authors.initials: GA
authors.lastname: Timco
authors.forename: Stergios
authors.initials: S
authors.lastname: Piligkos
authors.forename: Jennifer S
authors.initials: JS
authors.lastname: Mathieson
authors.forename: Hannu
authors.initials: H
authors.lastname: Mutka
authors.forename: Floriana
authors.initials: F
authors.lastname: Tuna
authors.forename: Piotr
authors.initials: P
authors.lastname: Kozlowski
authors.forename: Michal
authors.initials: M
authors.lastname: Antkowiak
authors.forename: Tatiana
authors.initials: T
authors.lastname: Guidi
authors.forename: Tulika
authors.initials: T
authors.lastname: Gupta
authors.forename: Harapriya
authors.initials: H
authors.lastname: Rath
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Woolfson
authors.forename: Grzegorz
authors.initials: G
authors.lastname: Kamieniarz
authors.forename: Robin G
authors.initials: RG
authors.lastname: Pritchard
authors.forename: Høgni
authors.initials: H
authors.lastname: Weihe
authors.forename: Leroy
authors.initials: L
authors.lastname: Cronin
authors.forename: Gopalan
authors.initials: G
authors.lastname: Rajaraman
authors.forename: David
authors.initials: D
authors.lastname: Collison
authors.forename: Eric J L
authors.initials: EJ
authors.lastname: McInnes
authors.forename: Richard E P
authors.initials: RE
authors.lastname: Winpenny