Investigations on the relationship between $T_c$ and the superconducting gap under magnetic and non-magnetic impurity substitutions in YBa${}_2$Cu${}_3$O${}_{7-\delta }$

M. Le Tacon, A. Sacuto, Y. Gallais +2

We report electronic Raman scattering measurements on optimally doped YBa2Cu3O7 where Zn or Ni impurities have been substituted by Cu. Using Raman selection rules, we have probed t…