Titanium pyrochlore magnets: how much can be learned from magnetization measurements?

TL;DR

This study provides detailed magnetization measurements of various titanium pyrochlore magnets at very low temperatures, revealing new features and behaviors that deepen understanding of their magnetic phase transitions and dynamics.

Contribution

It offers new low-temperature magnetization data on titanium pyrochlores, uncovering overlooked features and clarifying magnetic behaviors across different compounds.

Findings

Slow magnetization relaxation in Dy2Ti2O7 and Ho2Ti2O7 at low fields

Nearly hysteresis-free magnetization in high fields for spin-ice pyrochlores

Diverging susceptibility near critical field in Er2Ti2O7

Abstract

We report magnetization data for several titanium pyrochlore systems measured down to 0.5 K. The measurements, performed on single crystal samples in fields of up to 7 T, have captured the essential elements of the previously reported phase transitions in these compounds and have also revealed additional important features overlooked previously either because of the insufficiently low temperatures used, or due to limitations imposed by polycrystalline samples. For the spin-ice pyrochlores Dy2Ti2O7 and Ho2Ti2O7, an unusually slow relaxation of the magnetization has been observed in lower fields, while the magnetization process in higher fields is essentially hysteresis-free and does not depend on sample history. For the XY pyrochlore Er2Ti2O7, the magnetic susceptibility shows nearly diverging behaviour on approach to a critical field, HC = 13.5 kOe, above which the magnetization does not saturate but continues to grow at a significant rate. For the Heisenberg pyrochlore Gd2Ti2O7, the magnetic susceptibility shows a pronounced change of slope at both transition temperatures, TN1 = 1.02 K and TN2 = 0.74 K, contrary to the earlier reports.