Influence of naturally grown nanoparticles at the buffer layer in the flux pinning in YBa2Cu3O7 coated conductors

We have studied the influence of naturally grown SrTiO3 particles at the buffer layer surface on the in-field critical current density ( J(c)) dependence of coated conductors. The presence of the SrTiO3 particles induces the growth of extra-correlated pinning along the c-axis direction in the YBa2Cu3O7 films that thread samples as thick as 5 mu m. These correlated pinning centres produce a bigger c-axis peak and effectively reduce the Jc magnetic field ( H) decay characterized by a smaller exponent a of the Jc. H-alpha power law decay. This method opens up a new approach for how to increase Jc under an applied magnetic field without the need for an extra process. This study brings new meaning to the so-called optimal deposition conditions, since it will depend on the field and temperature region of the application.