Magneto-optical interband absorption in diluted magneticPb1−xMnxSe

Magneto-optical interband absorption was measured in ${\mathrm{Pb}}_{1\mathrm{-}\mathit{x}}$ ${\mathrm{Mn}}_{\mathit{x}}$Se (0<x<0.01) in Faraday and Voigt configurations. The observed splitting between right- and left-circularly-polarized light in Faraday configuration is in the same direction as observed with ${\mathrm{Pb}}_{1\mathrm{-}\mathit{x}}$ ${\mathrm{Mn}}_{\mathit{x}}$Te and opposite to ${\mathrm{Pb}}_{1\mathrm{-}\mathit{x}}$ ${\mathrm{Eu}}_{\mathit{x}}$Se. This indicates that the exchange interaction between localized magnetic moments and free holes is also ferromagnetic in ${\mathrm{Pb}}_{1\mathrm{-}\mathit{x}}$ ${\mathrm{Mn}}_{\mathit{x}}$Se. The data are analyzed in the framework of the molecular-field approximation for IV-VI compounds. Estimates for the exchange integrals are given. The exchange energies in ${\mathrm{Pb}}_{1\mathrm{-}\mathit{x}}$ ${\mathrm{Mn}}_{\mathit{x}}$Se are comparable to those found in ${\mathrm{Pb}}_{1\mathrm{-}\mathit{x}}$ ${\mathrm{Mn}}_{\mathit{x}}$Te but an order of magnitude larger than in ${\mathrm{Pb}}_{1\mathrm{-}\mathit{x}}$ ${\mathrm{Eu}}_{\mathit{x}}$Se.