Europium-151 Mössbauer spectra of some orthorhombic perovskites

Abstract

The ¹⁵¹Eu Mössbauer resonance in the orthorhombic perovskites EuMO₃(M = Cr, Mn, Fe, or Co) is broadened by unresolved hyperfine effects. It is shown that this can be attributed to a quadrupole interaction with a coupling constant of e²qQ_gca. –6.5 mm s^–1. This value is in good agreement with the predicted value for EuFeO₃ from a detailed crystal-field calculation. The induced magnetic exchange interactions which should occur at the europium ions in the solid solution EuFe_0.8Cr_0.2O₃ have been found to be much smaller than predicted, and possible reasons for this are discussed.