Effect of simultaneous addition of 1D and 3D artificial pinning centers in hybrid YBa₂Cu₃O_7-x multilayers

The nanoengineering approach by PLD method can produce a variety of complex nanocomposite oxide thin films with unique properties for sustainable applications. We report on the epitaxial growth and superconducting properties of YBa₂Cu₃O_7-x (YBCO) multilayers incorporating BaSnO₃ (BSO) nanorods and Y₂O₃ nanoparticles at the same time in order to combine the advantages of both columnar (1D, BSO) and isotropic (3D, Y₂O₃) pinning with the purpose of enhance the pinning force of the films for a wide range of applications in large external magnetic fields. Multilayered films, alternating YBCO+Y₂O₃ and YBCO+BSO layers were grown in pulsed laser deposition chamber by switching a surface-modified YBCO+~2A% Y₂O₃ target and a mixed YBCO+4 wt% BSO target. Different combinations for films' growth have been tried via varying the thickness of the alternating layers. The best result was obtained with the combination [(90 nm YBCO +BSO)/(30 nm YBCO+Y₂O₃)]×3 presenting a maximum global pinning force F^max _p = 17.6 GN/m³ (77 K, 2.2 T, B//c), more than 3 times larger than for typical pure YBCO films. These results demonstrate that the nanoengineering approach is at very advanced level: satisfactory control of nanodefects size and distribution was achieved. At the end, a renewed approach based on the Ginzburg-Landau single vortex theory is used to discuss the contributions of 1D, 3D and 1D+3D APCs to the global pinning force of the hybrid multilayers.