Two-magnon raman scattering and infrared absorption in (MnZn)F₂

Abstract

Measurements have been made of the Raman scattering and infrared absorption peaks arising from excitation of magnon pairs in the system (Mn1-cZnc)F2. Single crystals were investigated with c varying from 0 to 1. The measurements are compared with predictions of both a mean field model and an Ising cluster model. Approximate mean field values are obtained for the first, second and third moments of the two-magnon peak. The Ising model has been applied in a way that takes account of the proximity in pairs of the manganese atoms responsible for the two-magnon scattering and absorption and it gives a mean frequency that is higher than the mean field result although not quite as high as the experimental results.