Dynamic susceptibility of a spin ice near the critical point

TL;DR

This paper investigates the critical behavior of spin ice magnets near their critical point, revealing divergence in susceptibility and classifying the dynamics within a known universality class, with detailed calculations of corrections.

Contribution

It provides a theoretical analysis of the critical fluctuations in spin ice, including logarithmic corrections, and links their dynamics to the universality class of easy-axis ferroelectrics.

Findings

Longitudinal susceptibility diverges at the critical point.

Critical fluctuations follow the universality class of easy-axis ferroelectrics.

Logarithmic corrections to mean-field behavior are calculated.

Abstract

We consider spin ice magnets (primarily, $\mathrm{Dy_2Ti_2O_7}$) 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.