Does classical spin ice Dy_2Ti_2O_7 order or keep its Pauling entropy? · revision history

Revision 2

Accepted · core change · record

Changes against revision 1:

Title · changed
Revision 1: Does classical spin ice Dy2Ti2O7 order or keep its Pauling entropy?
Revision 2: Does classical spin ice $\mathrm{Dy_2Ti_2O_7}$ order or keep its Pauling entropy?
Plain
Ice-rule states are so numerous that spin ice keeps a leftover entropy at low temperature, as water ice does. Long-range dipolar forces predict an ordered state below about 0.2 K, but experiments struggle to reach equilibrium there.
Precise · changed · core
Revision 1: In Dy2Ti2O7, determine whether thermal equilibrium below 0.5 K approaches the ordered state predicted by the dipolar spin-ice model (transition near 0.18 K) with loss of the Pauling entropy $(R/2)\ln(3/2)$ per mole Dy, or retains a disordered ice manifold. An answer is the equilibrium entropy and any ordering wavevector as $T \to 0$.
Revision 2: In $\mathrm{Dy_2Ti_2O_7}$, determine whether thermal equilibrium below 0.5 K approaches the ordered state predicted by the dipolar spin-ice model (transition near 0.18 K) with loss of the Pauling entropy $(R/2)\ln(3/2)$ per mole Dy, or retains a disordered ice manifold. An answer is the equilibrium entropy and any ordering wavevector as $T \to 0$.
Settled by
Equilibrium heat capacity and neutron scattering below 0.3 K after controlled long annealing, compared with Monte Carlo of the fitted dipolar model.
Kind
well-posed
Answer type
yes-no
References
(empty)
Literature status
contested
Status note
Pomaranski et al. (Nature Physics 2013) found the residual entropy is lost after long equilibration without detecting the predicted order.
Posed since
2001

Decisions