AC Wien effect in spin ice, manifest in non-linear non-equilibrium susceptibility

TL;DR

This paper predicts a non-linear, non-equilibrium magnetic response in spin ice due to the AC Wien effect, revealing new regimes and symmetry properties that enhance understanding of Coulomb fluids of magnetic monopoles.

Contribution

It introduces the concept of an AC Wien effect in spin ice, showing how it affects monopole density and magnetization dynamics, with novel insights into frequency-dependent behaviors.

Findings

Identification of a frequency window with indistinguishable Wien effect in magnetolyte and electrolyte.

Discovery of a low-frequency regime where magnetization opposes the Wien effect.

Proposal of optimal parameters for observing the AC Wien effect in Dy$_2$Ti$_2$O$_7$.

Abstract

We predict the non-linear non-equilibrium response of a "magnetolyte", the Coulomb fluid of magnetic monopoles in spin ice. This involves an increase of the monopole density due to the second Wien effect---a universal and robust enhancement for Coulomb systems in an external field---which in turn speeds up the magnetization dynamics, manifest in a non-linear susceptibility. Along the way, we gain new insights into the AC version of the classic Wien effect. One striking discovery is that of a frequency window where the Wien effect for magnetolyte and electrolyte are indistinguishable, with the former exhibiting perfect symmetry between the charges. In addition, we find a new low-frequency regime where the growing magnetization counteracts the Wien effect. We discuss for what parameters best to observe the AC Wien effect in Dy$_2$Ti$_2$O$_7$.