Dynamics and thermodynamics of a topological transition in spin ice materials under strain

TL;DR

This study investigates the effects of magnetic field and uniaxial stress on Dy$_2$Ti$_2$O$_7$ and Ho$_2$Ti$_2$O$_7$ spin ice materials, revealing preserved gauge field features, a Kasteleyn transition, and stress-sensitive dynamics, especially in Ho$_2$Ti$_2$O$_7$.

Contribution

It demonstrates that spin ice properties are robust under strain and identifies the Kasteleyn transition experimentally, providing new insights into spin ice thermodynamics and dynamics.

Findings

Magnetisation shows upward convexity over a broad field range.

Static and dynamic susceptibilities exhibit a peculiar peak.

Uniaxial compression up to -0.8% does not significantly alter thermodynamics.

Abstract

We study single crystals of Dy$_2$Ti$_2$O$_7$ and Ho$_2$Ti$_2$O$_7$ under magnetic field and stress applied along their [001] direction. We find that many of the features that the emergent gauge field of spin ice confers to the macroscopic magnetic properties are preserved in spite of the finite temperature. The magnetisation vs. field shows an upward convexity within a broad range of fields, while the static and dynamic susceptibilities present a peculiar peak. Following this feature for both compounds, we determine a single experimental transition curve: that for the Kasteleyn transition in three dimensions, proposed more than a decade ago. Additionally, we observe that compression up to $-0.8\%$ along [001] does not significantly change the thermodynamics. However, the dynamical response of Ho$_2$Ti$_2$O$_7$ is quite sensitive to changes introduced in the ${\rm Ho}^{3+}$ environment. Uniaxial compression can thus open up experimental access to equilibrium properties of spin ice at low temperatures.