151Eu Mössbauer studies in the high Tc superconducting oxide materials

¹⁵¹Eu Mössbauer studies have been made across the respective superconductive transition temperatures in two compounds, La_1.7Eu_0.1Sr_0.2CuO_4?y and EuBa₂Cu₃O₇, having zero resistance state at 25K and 85K respectively. The¹⁵¹Eu isomer shift data establish that Eu ions are in trivalent state at all temperatures. The Mössbauer f-factor does not show any significant anomaly across the T_C.