title: Spin disorder and order in quasi-2D triangular Heisenberg antiferromagnets: comparative study of FeGa2S4, Fe2Ga2S5, and NiGa2S4.
abstract: Our single crystal study reveals that the single-layer S=2 triangular Heisenberg antiferromagnet FeGa2S4 forms a frozen spin-disordered state, similar to the S=1 isostructural magnet NiGa2S4. In this state, the magnetic specific heat C{M} is not only insensitive to the field, but shows a T2 dependence that scales to C{M} of NiGa2S4, suggesting the same underlying mechanism of the 2D coherent behavior. In contrast, the bilayer system Fe2Ga2S5 exhibits a 3D antiferromagnetic order.
authors.affiliation: Department of Physics, Kyoto University, Kyoto 606-8502, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Nakatsuji
authors.forename: H
authors.initials: H
authors.lastname: Tonomura
authors.forename: K
authors.initials: K
authors.lastname: Onuma
authors.forename: Y
authors.initials: Y
authors.lastname: Nambu
authors.forename: O
authors.initials: O
authors.lastname: Sakai
authors.forename: Y
authors.initials: Y
authors.lastname: Maeno
authors.forename: R T
authors.initials: RT
authors.lastname: Macaluso
authors.forename: Julia Y
authors.initials: JY
authors.lastname: Chan