title: Spin Liquid State in the 3D Frustrated Antiferromagnet PbCuTe_{2}O_{6}: NMR and Muon Spin Relaxation Studies.
abstract: PbCuTe_{2}O_{6} is a rare example of a spin liquid candidate featuring a three-dimensional magnetic lattice. Strong geometric frustration arises from the dominant antiferromagnetic interaction that generates a hyperkagome network of Cu^{2+} ions although additional interactions enhance the magnetic lattice connectivity. Through a combination of magnetization measurements and local probe investigations by NMR and muon spin relaxation down to 20 mK, we provide robust evidence for the absence of magnetic freezing in the ground state. The local spin susceptibility probed by the NMR shift hardly deviates from the macroscopic one down to 1 K pointing to a homogeneous magnetic system with a low defect concentration. The saturation of the NMR shift and the sublinear power law temperature (T) evolution of the 1/T_{1} NMR relaxation rate at low T point to a nonsinglet ground state favoring a gapless fermionic description of the magnetic excitations. Below 1 K a pronounced slowing down of the spin dynamics is witnessed, which may signal a reconstruction of spinon Fermi surface. Nonetheless, the compound remains in a fluctuating spin liquid state down to the lowest temperature of the present investigation.
authors.affiliation: Ames Laboratory, U.S. Department of Energy, Ames, Iowa 50011, USA.|Laboratoire de Physique des Solides, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91405 Orsay Cedex, France.
authors.forename: P
authors.initials: P
authors.lastname: Khuntia
authors.affiliation: Laboratoire de Physique des Solides, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91405 Orsay Cedex, France.
authors.forename: F
authors.initials: F
authors.lastname: Bert
authors.affiliation: Laboratoire de Physique des Solides, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91405 Orsay Cedex, France.
authors.forename: P
authors.initials: P
authors.lastname: Mendels
authors.affiliation: School of Physics, University of Hyderabad, Central University PO, Hyderabad 500046, India.|Center of Condensed Matter Sciences, National Taiwan University, Taipei 10617, Taiwan.
authors.forename: B
authors.initials: B
authors.lastname: Koteswararao
authors.affiliation: Department of Physics, Indian Institute of Technology Bombay, Powai, Mumbai-400076, India.
authors.forename: A V
authors.initials: AV
authors.lastname: Mahajan
authors.affiliation: Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Baenitz
authors.affiliation: Center of Condensed Matter Sciences, National Taiwan University, Taipei 10617, Taiwan.
authors.forename: F C
authors.initials: FC
authors.lastname: Chou
authors.affiliation: Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland.
authors.forename: C
authors.initials: C
authors.lastname: Baines
authors.affiliation: Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland.
authors.forename: A
authors.initials: A
authors.lastname: Amato
authors.affiliation: Ames Laboratory, U.S. Department of Energy, Ames, Iowa 50011, USA.|Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Furukawa