Dirty Spin Ice: The Effect of Dilution on Spin Freezing in Dy2Ti2O7

TL;DR

This study investigates how non-magnetic ion dilution affects spin freezing in Dy2Ti2O7, revealing that dilution reduces participating spins but preserves freezing temperature, indicating local correlations drive the freezing process.

Contribution

It provides new insights into the impact of site dilution on spin freezing and relaxation dynamics in spin ice materials.

Findings

Dilution decreases the number of spins involved in freezing.

Freezing temperature remains unchanged despite dilution.

Relaxation time distribution broadens slightly with dilution.

Abstract

We have studied spin freezing in the diluted spin ice compound Dy2-xYxTi2O7 where the non-magnetic Y ions replace the magnetic Dy ions on the frustrated pyrochlore lattice. Magnetic a.c. and d.c. susceptibility data are presented with an analysis of relaxation times for dilutions of x = 0, 0.1, 0.2, and 0.4. Site dilution apparently decreases the relative number of spins participating in the ice-like freezing near 16 K while leaving the freezing temperature unchanged. Correspondingly the distribution of relaxation times associated with the freezing is broadened only slightly with increasing dilution, suggesting that the freezing process observed near T = 16 K involves local correlations among the spins.