Study of Structure, Composition and Electromagnetic Properties of High Levels of Zr-Doped REBa2Cu3O7-x Tapes Fabricated by Metal Organic Chemical Vapor Deposition

In this thesis the critical currents (Ic), structural properties and composition variations of Zr-doped (Gd,Y)Ba2Cu3Ox (GdYBCO) superconducting tapes fabricated by metal organic chemical vapor deposition (MOCVD) were studied. By a modified MOCVD process, the self-field critical currents at 77K of GdYBCO with high Zr doping levels have been enhanced significantly. The in-field performances of critical currents of GdYBCO tapes with Zr-doping levels of 7.5-30 at.% were investigated up to 5 T over a temperature range of 40 K – 77 K. The tape with 20% Zr doping is found to have the highest minimum critical currents and the highest critical currents in orientation of the field perpendicular to the c-axis (H||c) over a wide range of temperatures and magnetic fields. The electromagnetic properties have been related to the microstructure changes. For finding out the optimal film composition with the best in-field performance at 30K, 3T, the influence of composition on in-field performance has also been studied.