Optical response due to many magnons inαFe2O3

Abstract
Two- and three-magnon excitations are observed both in the midinfrared absorption and Raman scattering spectrum of αFe2O3 crystals. The polarization and temperature dependence of these signals are well understood by group-theoretical analysis, and the microscopic mechanism is discussed for the midinfrared absorption due to two- and three-magnon excitations.