Nucleation and mesostrain influence on percolating critical currents of solution derived YBa2Cu3O7 superconducting thin films

► The nucleation process of ex situ and in situ grown YBCO thin films are compared. ► Ag additives widen the temperature window where c-axis nucleation can be achieved. ► The percolating critical currents are reduced by mesostrain at grain boundaries. ► Weak link behavior at grain boundaries persist when strain is not healed properly.