Manufacturing of coated conductors can be tailored for future use operating parameters, such as high temperature and low field, mid temperature and mid field and low temperature and high field. Different methods of flux pinning are being tested world-wide to enhance critical currents of high temperature superconductor yttrium barium copper oxide coated conductors for these various operating conditions. Previous studies have focused on single phase additions such as BaSnO₃ (BSO), BaZrO₃ (BZO), BaHfO₃ (BHO), Y₂BaCuO₅ (Y211), and magnetic additions such as BaFe₁₂O₁₉ (BFO), La_0.67Ca_0.33MnO₃ (LCMO), Y₃Fe₅O₁₂ (YIG), and SrRuO₃ (SRO). These additions have also been incorporated in multilayer composite films. However, the addition of several phases simultaneously, such as combining Y₂O₃ with BSO, BZO, and BHO, has shown strong improvements by combining different flux pinning mechanisms. This paper summarizes the results of these nanoparticle pinning additions. Pulsed laser deposition produced films on LaAlO₃ and SrTiO₃ substrates at deposition temperatures of 750-840 °C. Current density was measured for fields ranging from H = 0-9 T with H // c, and temperatures from 5-77 K, providing a detailed picture of pinning effects. Optimized results of flux pinning, magnetic current densities J_cm (H, T), critical transition temperatures (T_c), lattice parameters, and microstructures are presented.

Keywords: yttrium barium copper oxide, composite films, flux pinning, current density