Dynamic susceptibility of a spin ice near the critical point
A. V. Shtyk, M. V. Feigel'man
L.D. Landau Institute for Theoretical Physics RAS, 119334 Moscow, Russia
Moscow Institute of Physics and Technology, 141700 Moscow, Russia
We consider spin ice magnets (primarily, ) in
the vicinity of their critical point on the (H,T) plane. We
find that the longitudinal susceptibility diverges at the critical
point, leading to the behaviour qualitatively similar to the one
which would result from non-zero conductance of magnetic charges.
We show that dynamics of critical fluctuations belongs to the universality
class of easy-axis ferroelectric
and calculate logarithmic corrections (within two-loop approximation)
to the mean-field critical behavior.