# Nuclear spin assisted quantum tunnelling of magnetic monopoles in spin ice

## TL;DR

This paper demonstrates that nuclear-spin assisted quantum tunnelling influences the dynamics of magnetic monopoles in spin ice, revealing a new way to control emergent excitations in strongly correlated systems.

## Contribution

It shows that hyperfine interactions enable quantum tunnelling of magnetic monopoles in spin ice, extending the mechanism beyond single molecule magnets.

## Key findings

- Nuclear spins affect monopole hopping in spin ice.
- Hyperfine coupling brings monopole spins to resonance.
- Monopole current can be controlled via nuclear spin interactions.

## Abstract

Extensive work on single molecule magnets has identified a fundamental mode of relaxation arising from the nuclear-spin assisted quantum tunnelling of nearly independent and quasi-classical magnetic dipoles. Here we show that nuclear-spin assisted quantum tunnelling can also control the dynamics of purely emergent excitations: magnetic monopoles in spin ice. Our low temperature experiments were conducted on canonical spin ice materials with a broad range of nuclear spin values. By measuring the magnetic relaxation, or monopole current, we demonstrate strong evidence that dynamical coupling with the hyperfine fields bring the electronic spins associated with magnetic monopoles to resonance, allowing the monopoles to hop and transport magnetic charge. Our result shows how the coupling of electronic spins with nuclear spins may be used to control the monopole current. It broadens the relevance of the assisted quantum tunnelling mechanism from single molecular spins to emergent excitations in a strongly correlated system.