Selvamanickam, Venkat2019-11-08August 2012019-08August 201Portions of this document appear in: Pratap, Rudra, Goran Majkic, Eduard Galstyan, Girupaakaran Mohanasundaram, Sanku Chakradhar, and Venkat Selvamanickam. "Growth of High-Performance Thick Film REBCO Tapes Using Advanced MOCVD." IEEE Transactions on Applied Superconductivity 29, no. 5 (2019): 1-5. And in: Majkic, Goran, Rudra Pratap, Aixia Xu, Eduard Galstyan, Hugh C. Higley, Soren O. Prestemon, Xiaorong Wang, Dmytro Abraimov, Jan Jaroszynski, and Venkat Selvamanickam. "Engineering current density over 5 kA mm− 2 at 4.2 K, 14 T in thick film REBCO tapes." Superconductor Science and Technology 31, no. 10 (2018): 10LT01.https://hdl.handle.net/10657/5340Rare Earth Barium Copper Oxide (REBCO) coated conductors are the only superconductors with a potential for applications over broad range of temperature (77 K – 4.2 K) and wide range of fields (0 – 20 T and above). However, its high cost compared with other available superconductors is a major bottleneck in realizing its desired potential and wide range of applicability. Reducing cost of REBCO in terms of ($/kA-m) can be accomplished by further improving the engineering current density (Je) of these superconductors and reducing the manufacturing cost. Je can be improved in two different ways - by incorporating pinning centers and by increasing thickness (> 2 μm) without deterioration of critical current density (Jc). Increasing pinning centers has a certain limit, after which the critical current degrades. Increasing thickness of REBCO without any deterioration in Jc is a direct way forward to achieving high Je. However, increasing thickness (> 2 μm) of REBCO has always led to decrease in Jc, independent of the deposition method used. The major obstacle here is poor process control, a high Jc could not be maintained along the thickness, while growing thicker films (> 2 μm). In the present work, thick (3.5 -5 μm) undoped and doped REBCO films were grown using an advanced MOCVD (A-MOCVD) reactor. Several different studies have been conducted to optimize compositions in order to achieve high performance for high temperature, low field application with good isotropic behavior and for low temperature, medium - high field applications. Record high Ic of 1440 A/cm at 65 K, 1.5 T (B || c-axis) and a minimum Ic of 1740 A/cm at 65 K, 0.25 T have been attained in 4.7 μm 5 mol% Hf-doped REBCO films. Also, engineering current density (Je) over 5 kA/mm2 (∼ 5X Nb3Sn) has been achieved in a 4.8 μm thick, 15 mol% Zr-doped REBCO at 4.2 K, 14 T ( B parallel to c-axis).application/pdfengThe author of this work is the copyright owner. UH Libraries and the Texas Digital Library have their permission to store and provide access to this work. UH Libraries has secured permission to reproduce any and all previously published materials contained in the work. Further transmission, reproduction, or presentation of this work is prohibited except with permission of the author(s).High-temperature superconductorsMOCVDSuperconducting filmsFlux pinningCritical currentYBCOThick REBCO films2019-11-08Thesisborn digital