title: High-pressure sequence of Ba3NiSb2O9 structural phases: new S = 1 quantum spin liquids based on Ni2+.
abstract: Two new gapless quantum spin-liquid candidates with S = 1 (Ni(2+)) moments: the 6H-B phase of Ba(3)NiSb(2)O(9) with a Ni(2+)-triangular lattice and the 3C phase with a Ni(2/3)Sb(1/3)-three-dimensional edge-shared tetrahedral lattice were obtained under high pressure. Both compounds show no magnetic order down to 0.35 K despite Curie-Weiss temperatures θ(CW) of -75.5 (6H-B) and -182.5 K (3C), respectively. Below ~25 K, the magnetic susceptibility of the 6H-B phase saturates to a constant value χ(0) = 0.013 emu/mol, which is followed below 7 K by a linear-temperature-dependent magnetic specific heat (C(M)) displaying a giant coefficient γ = 168 mJ/mol K(2). Both observations suggest the development of a Fermi-liquid-like ground state. For the 3C phase, the C(M) perpendicular T(2) behavior indicates a unique S = 1, 3D quantum spin-liquid ground state.
authors.affiliation: Texas Materials Institute, University of Texas at Austin, Texas 78712, USA.
authors.forename: J G
authors.initials: JG
authors.lastname: Cheng
authors.forename: G
authors.initials: G
authors.lastname: Li
authors.forename: L
authors.initials: L
authors.lastname: Balicas
authors.forename: J S
authors.initials: JS
authors.lastname: Zhou
authors.forename: J B
authors.initials: JB
authors.lastname: Goodenough
authors.forename: Cenke
authors.initials: C
authors.lastname: Xu
authors.forename: H D
authors.initials: HD
authors.lastname: Zhou