Structural Disorder and Properties of the Stuffed Pyrochlore Ho2TiO5

TL;DR

This study investigates the structural and magnetic properties of Ho2TiO5, revealing that local structural differences influence magnetic behavior despite similar susceptibilities, with implications for understanding stuffed pyrochlore materials.

Contribution

It provides a comparative analysis of structural ordering and magnetic properties in Ho2TiO5 synthesized via different methods, highlighting the role of local structure.

Findings

Short-range pyrochlore ordering in defect fluorite phase

Long-range ordering in floating zone sample

Magnetic properties depend on local structural differences

Abstract

We report a structural and thermodynamic study of the "stuffed spin ice" material Ho2TiO5 (i.e., Ho2(Ti1.33Ho0.67)O6.67), comparing samples synthesized through two different routes. Neutron powder diffraction and electron diffraction reveal that the previously reported defect fluorite phase has short-range pyrochlore ordering, in that there are domains in which the Ho and Ho/Ti sublattices are distinct. By contrast, a sample prepared through a floating zone method has long range ordering of these sublattices. Despite the differences in crystal structures, the two versions of Ho2TiO5 display similar magnetic susceptibilities. Field dependent magnetization and measured recovered entropies, however, show a difference between the two forms, suggesting that the magnetic properties of the stuffed pyrochlores depend on the local structure.