Antiferromagnetic critical pressure in URu2Si2 under hydrostatic conditions

TL;DR

This study investigates the pressure-induced antiferromagnetic transition in URu2Si2 using neutron diffraction under near-hydrostatic conditions, revealing a higher critical pressure and a phase diagram where superconductivity and antiferromagnetism converge.

Contribution

It provides new measurements of the antiferromagnetic critical pressure under hydrostatic conditions and redefines the phase diagram of URu2Si2, showing the convergence of superconducting and antiferromagnetic phases.

Findings

Antiferromagnetic critical pressure is 0.80 GPa under hydrostatic conditions.

The hidden order-antiferromagnetic bicritical point exceeds 1.02 GPa.

Superconducting and antiferromagnetic phase boundaries meet at a common critical pressure.

Abstract

The onset of antiferromagnetic order in URu2Si2 has been studied via neutron diffraction in a helium pressure medium, which most closely approximates hydrostatic conditions. The antiferromagnetic critical pressure is 0.80 GPa, considerably higher than values previously reported. Complementary electrical resistivity measurements imply that the hidden order-antiferromagnetic bicritical point far exceeds 1.02 GPa. Moreover, the redefined pressure-temperature phase diagram suggests that the superconducting and antiferromagnetic phase boundaries actually meet at a common critical pressure at zero temperature.