High J }}} Coated Conductors on }-Buffered IBAD MgO Template Fabricated by Pulsed Laser Deposition

• Published in: IEEE transactions on applied superconductivity 2011-06, Vol.21 (3), p.2965-2968
• Main Authors: Ko, Kyoung-Pil, Moon, Seung-Hyun, Park, Chan, Yoo, Sang-Im
• Format: Article
• Language: English
• Subjects: Buffer layers; Conductors; Copper; Fabrication; GdBCO; IBAD MgO; Moon; PLD; Substrates; Yttrium barium copper oxide; {\hbox {CeO}}_{2} buffer
• ISSN: 1051-8223; 1558-2515
• DOI: 10.1109/TASC.2010.2090315

High quality GdBa 2 Cu 3 O 7-δ (GdBCO) coated conductors (CCs) were successfully fabricated on CeO 2 -buffered IBAD MgO template by pulsed laser deposition (PLD). With the same energy density of 2 J/cm 2 , laser frequency of 8 Hz, and oxygen pressure of 300 mTorr, both target-to-substrate distance ( D ts ) and substrate temperature ( T s ) were systematically varied from 5.5 to 4.0 cm at T s of 780 °C and from 760 to 820 °C at D ts of 4.5 cm, respectively, to investigate their effects on the grain alignment, microstructure, and superconducting properties of GdBCO films. Biaxially aligned GdBCO films without a -axis oriented GdBCO grains could be deposited at T s higher than 780 °C and D ts shorter than 5.0 cm. At T s of 760 °C, a small amount of a -axis oriented and 45 ° misaligned GdBCO grains was formed. The in-plane textures of GdBCO films were gradually improved when D ts decreased, while those were first improved with increasing T s up to 800 ° C and then degraded at 820 °C. The highest critical current density ( J c ) of 3.9 MA/cm 2 and critical current ( I c ) of 195 A/cm-width (77 K, self-field) were achieved from the 500 nm GdBCO film deposited at 800°C with D ts of 4.5 cm . The J c values of GdBCO films were found to be sensitive to the in-plane texture and also to the presence of a -axis oriented grains and 45° misaligned grains.