Critical current density in Ag/YBa2Cu3Ox and PrBa2Cu3Oy/YBa2Cu3Ox multilayers

One of the successful methods of introducing artificial artificial pinning centers in superconducting films is by alternating layers of superconducting material and incomplete layers (planar distributions of nanodots) of other materials (quasi-superlattice or quasi-multilayer approach). Most of the work on artificial pinning centers has been done on thin YBa2Cu3Ox (YBCO) films and a large variety of qusi-multilayer materials have been explored. It is still difficult to justify the choice of a quasi-multilayer material for particular superconducting applications. One of the properties to be taken into accounts is compatibility of the crystal lattice of YBCO and the quasi-superlattice material. Here we compare the superconducting behaviour of two very different quasi-multilayers: one with very similar crystal lattices of nanodots and YBCO: PrBa2Cu3Oy (PBCO)/YBCO, and another one with very different, Ag/YBCO. We found that the difference between crystal lattices strongly affects superconducting properties of quasi-multilayers and leads to different types of pinning in the films.