Influence of naturally grown nanoparticles at the buffer layer in the flux pinning in YBa2Cu3O7coated conductors

We have studied the influence of naturally grown SrTiO 3 particles at the buffer layer surface on the in-field critical current density ( J c ) dependence of coated conductors. The presence of the SrTiO 3 particles induces the growth of extra-correlated pinning along the c -axis direction in the YBa 2 Cu 3 O 7 films that thread samples as thick as 5 µm. These correlated pinning centres produce a bigger c -axis peak and effectively reduce the J c magnetic field ( H ) decay characterized by a smaller exponent α of the power law decay. This method opens up a new approach for how to increase J c 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.