Spin Correlations in Nearly FerromagneticEuxSr1xS

Abstract
High-resolution neutron-diffraction measurements have been performed on a single crystal of EuxSr1xS for x=0.52, an insulating spin system with competing exchange interactions. No detectable long-range magnetic order is observed at any temperature. However, intense magnetic diffuse scattering, well described by a Lorentzian, is present. As the temperatre is reduced from 6 to 0.4 K, the magnetic correlation length ξ increases to a resolution-limited maximum (> 400 Å) at 2.5 K, and subsequently decreases.