Pauling Entropy, Metastability, and Equilibrium in Dy_{2}Ti_{2}O_{7} Spin Ice

Area of Science:

• Condensed Matter Physics
• Thermodynamics
• Magnetism

Background:

• The third law of thermodynamics and Pauling entropy are crucial for understanding classical spin ice.
• Discrepancies exist between theoretical predictions and experimental observations regarding spin ice ordering transitions.

Purpose of the Study:

• To investigate the fate of Pauling entropy in Dy$_{2}$Ti$_{2}$O$_{7}$ at low temperatures.
• To reconcile experimental findings with the dipolar spin ice model and thermodynamic laws.

Main Methods:

• Neutron scattering and specific heat measurements at low temperatures and long timescales.
• High-resolution simulations of the neutron structure factor.
• Analysis of isotopic enrichment effects and hyperfine contributions.

Main Results:

• No evidence of reduced ice-rule correlations or spin entropy was found at low temperatures.
• Spin correlations are accurately described by the dipolar spin ice model across all tested temperatures.
• Previous entropy measurements using short-time relaxation were confirmed as accurate due to offsetting contributions.

Conclusions:

• The behavior of Dy$_{2}$Ti$_{2}$O$_{7}$ is consistent with the dipolar spin ice model and the third law of thermodynamics.
• The study validates the accuracy of earlier entropy measurements, resolving discrepancies in the field.