Mössbauer spectroscopy studies for YBa2 (Cu3−x,Snx)O7−δ

The high T c superconducting material YBa 2 (Cu 3−x , Sn x )O 7−δ with a large content of substitution element was studied by using 119 Sn Mossbauer spectroscopy. The work shows that with the content of substitution element up to x=1.0, T c is still higher than 80 K. The analysis of the Mossbauer spectrum has revealed that Sn ions substitute for ions at the Cu(1) site in YBa 2 Cu 3 O 7−δ . This has led us to conclude that ions at the Cu(2) site appear to play a decisive role in superconductivity