Angular-Dependent Vortex Pinning Properties of YBa 2 Cu 3 O 7− δ /Y 2 O 3 Quasi-Multilayers

A series of quasi-multilayers of YBa2Cu3O7−δ (YBCO)/Y2O3 specifically 70 × (m YBCO/n Y2O3) were prepared on SrTiO3 single crystal using pulsed-laser deposition (PLD) with a controlled deposition pulses of m = 40 and n = 2, 5, and 10 for YBCO and Y2O3, respectively. The x-ray diffraction patterns indicate that all the present quasi-multilayers exhibit good c-axis orientation. The angular dependence of critical current density (J c ) on applied magnetic field directions are systemically measured to study the anisotropic vortex pinning performances for those quasi-multilayers. It is revealed that compared with the pure YBCO films, the quasi-multilayers with n = 2, i.e., a proper constituent pulse of Y2O3, exhibits the enhanced vortex pinning abilities in all angles between c-axis orientation and the applied magnetic field direction. As well, such a quasi-multilayer film (n = 2) shows the higher lift factor J c (Θ)/ J c (90°) and much better vortex pinning properties at high fields and high temperatures, showing promising potential for coated conductor application.