Structural magnetic glassiness in spin ice Dy$_2$Ti$_2$O$_7$

TL;DR

This paper investigates the low-temperature magnetic behavior of Dy$_2$Ti$_2$O$_7$ spin ice, revealing it forms a 'structural magnetic glass' due to frustration and kinetic constraints, without structural disorder.

Contribution

It introduces the concept of a 'structural magnetic glass' in Dy$_2$Ti$_2$O$_7$, supported by experimental and numerical evidence, highlighting a new form of magnetic glass formation.

Findings

Spins freeze into a magnetic glass state at low temperatures.

The glassy state arises without chemical or structural disorder.

Frustration occurs on two levels, leading to kinetic constraints.

Abstract

The spin ice compound Dy$_2$Ti$_2$O$_7$ is well-known to realise a three-dimensional Coulomb spin liquid with magnetically charged monopole excitations. Its fate at low temperatures, however, remains an intriguing open question. Based on a low-temperature analysis of the magnetic noise and diffuse neutron scattering under different cooling protocols, combined with extensive numerical modelling, we argue that upon cooling, the spins freeze into what may be termed a `structural magnetic glass', without an a priori need for chemical or structural disorder. Specifically, our model indicates the presence of frustration on two levels, first producing a near-degenerate constrained manifold inside which phase ordering kinetics is in turn frustrated. Our results suggest that spin ice Dy$_2$Ti$_2$O$_7$ provides one prototype of magnetic glass formation specifically, and a setting for the study of kinetically constrained systems more generally.