Nb Substitution Effects on Superconducting Properties of<b>Ru</b><sub><b>1</b><b>−</b><b><i>x</i></b></sub><b>Nb</b><sub><b><i>x</i></b></sub><b>Sr</b><sub><b>2</b></sub><b>Eu</b><sub><b>1.4</b></sub><b>Ce</b><sub><b>0.6</b></sub><b>Cu</b><sub><b>2</b></sub><b>O</b><sub><b>10</b><b>−</b><b><i>δ</i></b></sub>
Advances in condensed matter physics