Influence of Zr and Ce doping on electromagnetic properties of (Gd,Y)–Ba–Cu–O superconducting tapes fabricated by metal organic chemical vapor deposition

Abstract

(Gd,Y)Ba 2Cu 3O x tapes have been fabricated by metal organic chemical vapor deposition (MOCVD) with Zr-doping levels of 0–15 mol.% and Ce doping levels of 0–10 mol.% in 0.4 μm thick films. The critical current density ( J c) of Zr-doped samples at 77 K, 1 T applied in the orientation of H ‖ c is found to increase with Zr content and shows a maximum at 7.5% Zr doping. The 7.5% Zr-doped sample exhibits a critical current density ( J c) of 0.95 MA/cm 2 at H ‖ c which is more than 70% higher than the J c of the undoped sample. The peak in J c at H ‖ c is 83% of that at H ‖ a– b in the 7.5% Zr-doped sample which is more than twice as that in the undoped sample. Superconducting transition temperature ( T c) values as high as about 89 K have been achieved in samples even with 15% Zr and 10% Ce. Ce-doped samples with and without Ba compensation are found to exhibit substantially different J c values as well as angular dependence characteristics.