Towards optimal BZO nanorod distribution in YBCO/Ca-YBCO multilayers

BaZrO 3 (BZO) nanorod-doped YBa 2 Cu 3 O 6 + x (YBCO) thin films with single-layer and multilayer architectures were fabricated to investigate the combined effects of artificial pinning centres and multilayering on flux pinning and critical current performance. Structural analyses show that Ca-doped YBCO interlayers improve crystalline quality and promote the growth of straighter, more uniformly distributed BZO nanorods. As a result, multilayer films exhibit superior in-field performance at 10 K in magnetic fields ranging from 0 T to 7 T, with the 6 wt.% BZO multilayer showing a J c enhancement of 30%–40 % compared with the corresponding single-layer film and up to 500 % relative to undoped YBCO at 10 K in 7 T field. Angular-dependent transport measurements at 70 K reveal improved isotropy of J c , while comparison with vortex-dynamics simulations indicates that the Ca-doped YBCO interlayers effectively reset nanorod growth between adjacent layers, eliminating lateral spatial correlations. These results demonstrate that BZO-doped multilayer YBCO architectures provide an effective route towards next-generation coated conductors for high-field superconducting applications.