Enhanced Magnetic‐Flux Pinning Through High‐Density Vertically Aligned BaCuO 2 Nanorods in Gd 0.5 Yb 0.5 Ba 2 Cu 3 O 7‐δ Films

Abstract A novel flux‐pinning design for REBa 2 Cu 3 O 7‐δ (REBCO) films intended for high‐field magnet applications is proposed, which is based on BaCuO 2 nanorods in Gd 0.5 Yb 0.5 Ba 2 Cu 3 O 7‐δ (Gd 0.5 Yb 0.5 BCO) films. The metal–organic chemical vapor deposition (MOCVD) process has been developed to achieve the desired microstructure. The influence of MOCVD parameters on the microstructure and critical current behavior of Gd 0.5 Yb 0.5 BCO films is systematically investigated. The morphology and density of BaCuO 2 crystallites within the films are highly sensitive to deposition temperature, oxygen partial pressure, and deposition rate. Notably, forming thin, elongated, vertically aligned BaCuO 2 nanorods requires precise control within a narrow processing window for these three parameters. The optimized MOCVD process results in a dense array of vertically aligned BaCuO 2 nanorods within the Gd 0.5 Yb 0.5 BCO film, significantly enhancing magnetic‐flux pinning, particularly in the low‐temperature and high‐magnetic‐field regime. Superconducting tapes coated with Gd 0.5 Yb 0.5 BCO films using the optimized MOCVD process exhibit a power‐law exponent ( α value) of 0.40 for the critical current decay with magnetic field at 4 K, which is substantially lower than that of other REBCO coated conductors reported to date.