High-magnetic field lattice length changes in URu2Si2

TL;DR

This study investigates how high magnetic fields affect the lattice length and phase transitions in URu2Si2, revealing discontinuities and phase re-entrance, and suggests a quantum critical point near 38 T.

Contribution

It provides detailed measurements of lattice length changes under high magnetic fields, identifying phase boundaries and the potential quantum critical point in URu2Si2.

Findings

Discontinuous length change at hidden order transition above 25 T

Observation of re-entrant phase III above 36 T

Sign change in thermal-expansion coefficient at 38 T

Abstract

We report high magnetic field (up to 45 T) c-axis thermal expansion and magnetostriction experiments on URu2Si2 single crystals. The sample length change associated with the transition to the hidden order phase becomes increasingly discontinous as the magnetic field is raised above 25 T. The re-entrant ordered phase III is clearly observed in both the thermal expansion and magnetostriction above 36 T, in good agreement with previous results. The sample length is also discontinuous at the boundaries of this phase, mainly at the upper boundary. A change in the sign of the coefficient of thermal-expansion is observed at the metamagnetic transition (B_M = 38 T) which is likely related to the existence of a quantum critical end point.