H-T phase diagram of the metamagnetic transition in $URu_2Si_2$, measured in high d. c. magnetic fields

TL;DR

This study maps the H-T phase diagram of $URu_2Si_2$ under high magnetic fields, revealing a hysteresis and a new phase separation line, highlighting differences from previous measurements due to magnetocaloric effects.

Contribution

First detailed H-T phase diagram of $URu_2Si_2$ in high magnetic fields, identifying hysteresis and a new phase separation line.

Findings

Hysteresis observed at low temperatures.

A new phase separation line detected.

Differences from earlier pulsed field measurements explained by magnetocaloric effect.

Abstract

We have studied the ultrasonic velocity and ac susceptibility of $URu_2Si_2$ in d. c. magnetic fields up to 45T. A significant difference between the constructed H-T phase diagram and that extracted from earlier pulsed fields measurements can be explained in terms of a large magnetocaloric effect. A hysteresis of metamagnetic transition at low temperatures and a new phase separation line have been observed for the first time.