Mössbauer spectroscopy study on double rare-earth orthoferrites Eu_0.2R_0.8FeO₃ (R=rare earth)

Double rare-earth ferrites Eu_0.2R_0.8FeO₃ (R=rare earth) are synthesized by a high-temperature method. X-ray-diffraction determinations show that all the compounds possess orthorhombic structure. Both ¹⁵¹Eu and ⁵⁷Fe Mössbauer spectra are measured. The results indicate that the isomer shift of the ¹⁵¹Eu nucleus depends on the unit-cell volume of Eu_0.2R_0.8FeO₃, and the quadrupole interaction of ¹⁵¹Eu Mössbauer spectra is relative to the inverse of the unit-cell volume. The hyperfine field parameter of ⁵⁷Fe Mössbauer spectra increases linearly with increasing unit-cell volume.