Magnetic properties of xCr2O3· (1 − x)[Bi2O3· PbO] glasses

EPR and magnetic susceptibility measurements have been performed on xCr2O3· (1 − x)[Bi2O3· PbO] glasses with 0 <x≤ 30 mol%. These data show that the chromium ions are in the Cr3+valence state. For x≤ 5 mol% most of these ions are isolated or experience dipole-dipole interactions, but for higher Cr2O3concentrations the dominant part of them are magnetically coupled by negative superexchange interactions.