Magnetothermal study of Dy Stuffed Spin Ice: Dy2(DyxTi2-x)O7-x/2

TL;DR

This study investigates the thermodynamic properties of Dy-stuffed spin ice, revealing entropy loss at higher doping levels and persistent spin fluctuations at low temperatures, possibly due to local structural domains.

Contribution

It provides new insights into the thermodynamics and spin dynamics of Dy-stuffed spin ice, highlighting differences from Ho analogs and suggesting structural domain effects.

Findings

Loss of spin ice entropy for x >= 0.3

Persistent spin fluctuations down to T ~ 0

Presence of local structural order domains

Abstract

We have studied the thermodynamics of the stuffed spin ice material, Dy2(DyxTi2-x)O7-x/2, in which additional Dy3+ replace Ti4+ in the pyrochlore Dy2Ti2O7. Heat capacity measurements indicate that these materials lose the spin ice zero point entropy for x >= 0.3, sharply contrasting with results on the analogous Ho materials. A finite ac susceptibility is observed as T ~ 0 in both the Ho and Dy materials with x = 0.67, which suggests that spin fluctuations persist down to T ~ 0. We propose that both the entropy and susceptibility data may be explained as a result of domains of local pyrochlore type structural order in these materials.