151Eu and57Fe Mössbauer and X-ray diffraction study of high temperature Tl-containing superconductor

⁵⁷Fe and¹⁵¹Eu Mössbauer spectroscopy and X-ray diffractometry measurements were performed with europium and iron containing Tl₂(Ca_0.8Eu_0.2)Ba₂(Cu_0.98Fe_0.02)₂O₈ and EuBa₂Cu₃O_7-d high temperature superconductor samples in order to study the effect of europium incorporated in a Tl-containing high temperature superconductor. Significant differences have been found between the⁵⁷Fe Mössbauer spectra of Tl-containing samples with and without Eu or between the¹⁵¹Eu Mössbauer spectra of Tl-containing and 1-2-3 type superconductors. The results can be interpreted by assuming that Eu can be localized at the Ca site in the Tl-containing superconductor.