div class=trans-pagebuttonPage 1button div class=trans-image amp-img class=trans-thumb alt=Page 1: Synthesis structure and superconducting properties of metastable YBa2−xYxCu3O7+δ src=https:reader031fdocumentorgreader031viewer2022020523575068791a28ab0f07b055cdhtml5thumbnails1jpg width=142 height=106 layout=responsive amp-img divp© 1988 Nature Publishing Grouppdivdiv class=trans-pagebuttonPage 2button div class=trans-image amp-img class=trans-thumb alt=Page 2: Synthesis structure and superconducting properties of metastable YBa2−xYxCu3O7+δ src=https:reader031fdocumentorgreader031viewer2022020523575068791a28ab0f07b055cdhtml5thumbnails2jpg width=142 height=106 layout=responsive amp-img divp© 1988 Nature Publishing Grouppdivdiv class=trans-pagebuttonPage 3button div class=trans-image amp-img class=trans-thumb alt=Page 3: Synthesis structure and superconducting properties of metastable YBa2−xYxCu3O7+δ src=https:reader031fdocumentorgreader031viewer2022020523575068791a28ab0f07b055cdhtml5thumbnails3jpg width=142 height=106 layout=responsive amp-img divp© 1988 Nature Publishing Grouppdiv