title: Gapless spin liquid ground state in the S = 1/2 vanadium oxyfluoride kagome antiferromagnet [NH4]2[C7H14N][V7O6F18].
abstract: The vanadium oxyfluoride [NH(4)](2)[C(7)H(14)N][V(7)O(6)F(18)] (DQVOF) is a geometrically frustrated magnetic bilayer material. The structure consists of S = 1/2 kagome planes of V(4+) d(1) ions with S = 1 V(3+) d(2) ions located between the kagome layers. Muon spin relaxation measurements demonstrate the absence of spin freezing down to 40 mK despite an energy scale of 60 K for antiferromagnetic exchange interactions. From magnetization and heat capacity measurements we conclude that the S = 1 spins of the interplane V(3+) ions are weakly coupled to the kagome layers, such that DQVOF can be viewed as an experimental model for S = 1/2 kagome physics, and that it displays a gapless spin liquid ground state.
authors.affiliation: CSEC and School of Chemistry, The University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom.
authors.forename: L
authors.initials: L
authors.lastname: Clark
authors.affiliation: Laboratoire de Physique des Solides, UMR CNRS, Université Paris-Sud, 91504 Orsay, France.
authors.forename: J C
authors.initials: JC
authors.lastname: Orain
authors.affiliation: Laboratoire de Physique des Solides, UMR CNRS, Université Paris-Sud, 91504 Orsay, France.
authors.forename: F
authors.initials: F
authors.lastname: Bert
authors.affiliation: CSEC and School of Chemistry, The University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom.
authors.forename: M A
authors.initials: MA
authors.lastname: De Vries
authors.affiliation: School of Chemistry and EaSTChem, University of St. Andrews, St. Andrews KY16 9ST, United Kingdom.
authors.forename: F H
authors.initials: FH
authors.lastname: Aidoudi
authors.affiliation: School of Chemistry and EaSTChem, University of St. Andrews, St. Andrews KY16 9ST, United Kingdom.
authors.forename: R E
authors.initials: RE
authors.lastname: Morris
authors.affiliation: School of Chemistry and EaSTChem, University of St. Andrews, St. Andrews KY16 9ST, United Kingdom.
authors.forename: P
authors.initials: P
authors.lastname: Lightfoot
authors.affiliation: ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX110QX, United Kingdom.
authors.forename: J S
authors.initials: JS
authors.lastname: Lord
authors.affiliation: ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX110QX, United Kingdom and Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, United Kingdom.
authors.forename: M T F
authors.initials: MT
authors.lastname: Telling
authors.affiliation: Service de Physique de l'État Condensé, CEA-CNRS, CE-Saclay, F-91191 Gif-Sur-Yvette, France.
authors.forename: P
authors.initials: P
authors.lastname: Bonville
authors.affiliation: CSEC and School of Chemistry, The University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom.
authors.forename: J P
authors.initials: JP
authors.lastname: Attfield
authors.affiliation: Laboratoire de Physique des Solides, UMR CNRS, Université Paris-Sud, 91504 Orsay, France and Institut Universitaire de France, 103 bd Saint Michel, F-75005 Paris, France.
authors.forename: P
authors.initials: P
authors.lastname: Mendels
authors.affiliation: CSEC and School of Chemistry, The University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom and Institut Laue Langevin, 6 Rue Jules Horowitz, 38042 Grenoble Cedex 9, France.
authors.forename: A
authors.initials: A
authors.lastname: Harrison