Mossbauer Effect Studied in the Double Rare-Earth Oxides LnEuO3

For the first time, the double rare-earth oxides LaEuO3, PrEuO3, NdEuO3, SmEuO3 were synthesized by using high pressure and high temperature method. The analyses of X-ray diffraction show that LaEuO3 is A-type (hexagonal) structure; PrEuO3, NdEuO3 and SmEuO3 are of B-type (monoclinic) structure; CeEuO3.5 is of F-type (fluorite) structure. Mossbauer spectra were measured using the 21.6 keV -ray of 151Eu at room temperature. It has been observed that the hyperfine interactions depend strongly on the ligand volume of Eu ions. This volume effect of the isomer shift can be mainly attributed to the distortion of 5s shell of Eu ions.