Spin disorder and order in quasi-2D triangular Heisenberg antiferromagnets: comparative study of FeGa2S4, Fe2Ga2S5, and NiGa2S4.
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.
Nakatsuji
S
S
Department of Physics, Kyoto University, Kyoto 606-8502, Japan.
Tonomura
H
H
Onuma
K
K
Nambu
Y
Y
Sakai
O
O
Maeno
Y
Y
Macaluso
R T
RT
Chan
Julia Y
JY