Gapless Spin Liquid Ground State in the S = 1 / 2 Vanadium Oxyfluoride Kagome Antiferromagnet [ NH 4 ] 2 [ C 7 H 14 N ] [ V 7 O 6 F 18 ]

L. Clark (1) , J. C. Orain (2) , F. Bert (2) , A. de Vries (1) , F. H. Aidoudi (3) , R. E. Morris (3) , P. Lightfoot (3) , J. S. Lord (4) , M. T. F. Telling (4) , P. Bonville (5) , P. Attfield (1) , P. Mendels (6, 2) , A. Harrison (7, 1)

1 Edin. - University of Edinburgh
2 LPS - Laboratoire de Physique des Solides
3 School of Chemistry [University of St Andrews]
4 ISIS Facility
5 LNO - Laboratoire Nano-Magnétisme et Oxydes
6 IUF - Institut universitaire de France
7 ILL - Institut Laue-Langevin

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.

Domaines: Physique [physics]

L. Clark, J. C. Orain, F. Bert, A. de Vries, F. H. Aidoudi, et al.. Gapless Spin Liquid Ground State in the S = 1 / 2 Vanadium Oxyfluoride Kagome Antiferromagnet [ NH 4 ] 2 [ C 7 H 14 N ] [ V 7 O 6 F 18 ]. Physical Review Letters, 2013, 110 (20), ⟨10.1103/PhysRevLett.110.207208⟩. ⟨cea-01477926⟩