High-resolution x-ray and neutron-scattering experiments have been performed on the same sample of ${\mathrm{KMnF}}_3$ in order to compare the temperature behavior of the neutron ‘‘central peak’’ and of the x-ray ‘‘quasi-Bragg’’ peak. It is found that the peak intensity of both the central and quasi-Bragg peaks evolves similarly as (T-${\mathit{T}}_{\mathit{c}}$${)}^{\mathrm{-}\gamma }$ with ${\gamma }_{\mathrm{CP}}$=1.34±0.08 and ${\gamma }_{\mathrm{QBP}}$=1.26±0.04. This result, together with considerations about experimental conditions, strongly suggests that the central peak and the quasi-Bragg peak are the same feature even if they are not observed in the same range of temperature.

• Received 6 July 1990

DOI:https://doi.org/10.1103/PhysRevB.42.8255