Two-magnon Raman scattering in KMnF3

Abstract
The two-magnon Raman spectrum of KMnF3 has been investigated as a function of temperature, and peak position and width parameters obtained. A Green function theory developed by Balucani and Tognetti (1973) is applied to the results and accurately describes the observed temperature dependence for T/TN3 can be adequately represented by the cubic perovskite structure despite structural distortions and the spin canting for temperatures below 81K. The Raman results predict a value of 4.98+or-0.07 cm-1 for the isotropic Heisenberg exchange constant.