Effect of pressure on tiny antiferromagnetic moment in the heavy-electron compound URu2Si2

Abstract

We have performed elastic neutron-scattering experiments on the heavy-electron compound URu2Si2 for pressure P up to 2.8 GPa. We have found that the antiferromagnetic (100) Bragg reflection below Tm ∼ 17.5K is strongly enhanced by applying pressure. For P < 1.1GPa, the staggered moment μo at 1.4 K increases linearly from ∼0.017(3)μB to ∼0.25(2)μB, while Tm increases slightly at a rate ∼1K/GPa, roughly following the transition temperature To determined from macroscopic anomalies. We have also observed a sharp phase transition at Pc ∼1.5GPa, above which a 3D-Ising type of antiferromagnetic phase ( μo∼0.4μB) appears with a slightly reduced lattice constant. 1999 © The American Physical Society.