X-ray magnetic scattering in antiferromagneticURu2Si2

Abstract

X-ray-resonance magnetic scattering has been used to study antiferromagnetic ordering in the small-moment (μ¯≃0.02${\mathrm{\mu }}_{\mathit{B}}$) heavy-fermion superconductor ${\mathrm{URu}}_2$ ${\mathrm{Si}}_2$. The intensity of the magnetic (003) reflection develops abruptly at ${\mathit{T}}_{\mathit{N}}$≃17 K and grows linearly to T=3 K, where it saturates. Long-range antiferromagnetic order (${\mathrm{\zeta }}_{003}^{\mathit{c}}$≃450 Å) persists into the superconducting state at ${\mathit{T}}_{\mathit{c}}$=1.3 K demonstrating the microscopic coexistence of these two ground states. At saturation, a remarkable peak intensity of 8 counts/sec was measured.