Neutron Scattering Study of the Long-Range Ordered State in CeRu₂Al₁₀

Abstract

Elastic and inelastic neutron scattering measurements have been performed on\npowder and single-crystal samples of orthorhombic CeRu2Al10. The order forming\nbelow T0 = 27 K was identified as a long-range antiferromagnetic state with the\nwave vector k = (1,0,0). The magnetic spectral response in the ordered phase,\nmeasured on powder, is characterized by a spin gap and a pronounced peak at 8\nmeV, whose Q dependence suggests a magnetic origin. Both features are\nsuppressed when temperature is raised to T0, and a conventional relaxational\nbehavior is observed at 40 K. This peculiar spin dynamics is discussed in\nconnection with recent magnetization results for the same compound.\n