2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/157797We report planar tunneling measurements on thin films of YBa$_2$Cu$_3$O$_{7-x}$ at various doping levels under magnetic fields. By choosing a special setup configuration, we have probed a field induced energy scale that dominates in the vicinity of a node of the d-wave superconducting order parameter. We found a high doping sensitivity for this energy scale. At Optimum doping this energy scale is in agreement with an induced $id_{xy}$ order parameter. We found that it can be followed down to low fields at optimum doping, but not away from it.9 pages, 8 figures, accepted for publication in Phys. Rev. BSuperconductivityStrongly Correlated Electronstext