X-ray magnetic scattering in antiferromagnetic URu2Si2

X-ray-resonance magnetic scattering has been used to study antiferromagnetic ordering in the small-moment (μ¯≃0.02μB) heavy-fermion superconductor URu2Si2. The intensity of the magnetic (003) reflection develops abruptly at TN≃17 K and grows linearly to T=3 K, where it saturates. Long-range antiferromagnetic order (ζ003c≃450 Å) persists into the superconducting state at Tc=1.3 K demonstrating the microscopic coexistence of these two ground states. At saturation, a remarkable peak intensity of 8 counts/sec was measured.