Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України
Abstract
The quasi-two-dimensional antiferromagnet CsDy(MoO₄)₂ is studied by neutron diffraction
and quasielastic neutron scattering. The crystal structure of two low-temperature phases (below
120 K and below 40 K) is determined. An approximate structure of the magnetically ordered phase
(TN = 1.36 K) is proposed. In the ordered state the order-parameter critical exponent β = 0.17(0.01),
the in-plane correlation length exponent ν = 0.94(0.07), and the staggered susceptibility critical index
γ= 1.01(0.04) were determined. Comparing these results to the exact solution for a 2D Ising
magnet we conclude that, although 2D behavior is apparent in CsDy(MoO₄)₂, there are deviations
from the simple 2D Ising model
