Low-temperature muon spin rotation studies of the monopole charges and currents in Y doped Ho2Ti2O7

TL;DR

This study uses muon spin rotation to investigate magnetic monopoles and their currents in Y-doped Ho2Ti2O7 spin ice at low temperatures, revealing monopole dynamics and magnetic behavior influenced by Y doping.

Contribution

It provides new experimental insights into monopole charges and currents in Y-doped Ho2Ti2O7 using muon spin rotation at very low temperatures.

Findings

Linear field dependence of muon relaxation rate observed in low Y-doped samples.

Magnetic field effects penetrate into the silver sample plate, indicating complex magnetic dynamics.

Y doping influences the magnetic monopole behavior in spin ice.

Abstract

In the ground state of Ho2Ti2O7 spin ice, the disorder of the magnetic moments follows the same rules as the proton disorder in water ice. Excitations take the form of magnetic monopoles that interact via a magnetic Coulomb interaction. Muon spin rotation has been used to probe the low-temperature magnetic behaviour in single crystal Ho2-xYxTi2O7 (x=0, 0.1, 1, 1.6 and 2). At very low temperatures, a linear field dependence for the relaxation rate of the muon precession lambda(B), that in some previous experiments on Dy2Ti2O7 spin ice has been associated with monopole currents, is observed in samples with x=0, and 0.1. A signal from the magnetic fields penetrating into the silver sample plate due to the magnetization of the crystals is observed for all the samples containing Ho allowing us to study the unusual magnetic dynamics of Y doped spin ice.