Measurement of spin-correlation lengths inEu0.54Sr0.46S by elastic light scattering

Elastic light scattering has been used to measure the spin-correlation length ξ, in the reentrant spin-glass ${\mathrm{Eu}}_{0.54}$ ${\mathrm{Sr}}_{0.46}$S. ξ is found to change only modestly as one goes from the ferromagnetic to the spin-glass (SG) phase, i.e., from 2700 to 2000 Å. This result may be reconciled with neutron experiments which find ξ∼100 Å in the SG regime by ascribing the light scattering in the SG regime to the remanent magnetization of the original ferromagnetic regions.