First order metamagnetic transition in Ho2Ti2O7 observed by vibrating coil magnetometry at milli-Kelvin temperatures

TL;DR

This study investigates the first-order metamagnetic transition in Ho2Ti2O7 spin ice using vibrating coil magnetometry at milli-Kelvin temperatures, revealing a critical endpoint and similarities with Dy2Ti2O7.

Contribution

It provides the first detailed characterization of the metamagnetic transition and critical endpoint in Ho2Ti2O7, expanding understanding of spin ice magnetic behavior.

Findings

Identification of a first order metamagnetic transition

Observation of a critical endpoint at T*_m ~ 0.37 K

Similarity of transition features with Dy2Ti2O7

Abstract

We report vibrating coil magnetometry of the spin ice system Ho2Ti2O7 down to ~0.04 K for magnetic fields up to 5 T applied parallel to the [111] axis. History dependent behavior emerges below T*_0 ~ 0.6 K near zero magnetic field, in common with other spin ice compounds. In large magnetic fields we observe a magnetization plateau followed by a hysteretic metamagnetic transition. The temperature dependence of the coercive fields as well as the susceptibility calculated from the magnetization identify the metamagnetic transition as a line of first order transitions terminating in a critical endpoint at T*_m ~ 0.37 K, B*_m ~ 1.5 T. The metamagnetic transition in Ho2Ti2O7 is strongly reminiscent of that observed in Dy2Ti2O7, suggestive of a general feature of the spin ices.