Optimization of the \hbox Doping Content in \hbox\hbox\hbox Coated Conductors by Pulsed Laser Deposition

• Published in: IEEE transactions on applied superconductivity 2014-12, Vol.24 (6), p.1-8
• Main Authors: Kyung-Pil Ko, Soon-Mi Choi, Jung-Woo Lee, Rock-Kil Ko, Seung-Hyun Moon, Chan Park, Sang-Im Yoo
• Format: Article
• Language: English
• Subjects: Critical current density (superconductivity); Doping; field-orientation dependence of J_{c}; hbox{BaSnO}_{3} (BSO) nanorods; hbox{GdBa}_{2}\hbox{Cu}_{3}\hbox{O}_{7-\delta} (GdBCO); High-temperature superconductors; Magnetic hysteresis; pinning force density; Pulsed layer deposition; Superconducting thin films; transmission electron microscopy (TEM); Yttrium barium copper oxide
• ISSN: 1051-8223; 1558-2515
• DOI: 10.1109/TASC.2014.2338296

We tried to optimize the BaSnO 3 (BSO) doping content in GdBa 2 Cu 3 O 7-δ (GdBCO) coated conductors (CCs) on CeO 2 -buffered ion-beam assisted deposition (IBAD)-MgO templates. The BSO-doped GdBCO CCs with various x vol% ( x=0, 2, 3, 4, 5, and 6) relative to GdBCO were prepared at 800°C with the oxygen pressure of 300 mtorr by pulsed laser deposition (PLD), and their pinning properties were characterized by measuring magnetic hysteresis curves for the applied field parallel to the c-axis of GdBCO (B//c) up to 5 T and field-orientation dependence of transport critical currents for 1, 3, and 5 T at 65 and 77 K, respectively. Among all samples, a 5 vol% BSO-doped GdBCO CC exhibited the highest maximum pinning force density (F p,max ) values of 32.5 GN/m 3 near 4 T at 65 K and 6.5 GN/m 3 near 3.2 T at 77 K, for B//c (θ = 180 ° ), and also the highest minimum transport critical current density (Jc,min) of 0.39 MA/cm 2 at 77 K in 1 T and 0.68 MA/cm 2 at 65 K in 3 T, for θ = 120 ° , evidencing that 5 vol% is the optimum BSO content. Observation of BSO-doped GdBCO CCs by transmission electron microscopy revealed that the effective flux pinning of BSO-doped GdBCO CC was attributed to the BSO nanorods of ~ 10-nm diameters roughly aligned along the c-axis of the GdBCO matrix.