GdBa(2)Cu(3)O(x) for microwave applications: preparation, properties and devices

• Published in: IEEE transactions on applied superconductivity Vol. 3; no. 1; pp. 1733 - 1736
• Main Authors: Jedamzik, D, Trowles, T P, Zammattio, S J, Stephan, R E, Lamacraft, K, Phillips, W A, Hedges, S J, Adams, M, Nicholson, B F
• Format: Journal Article
• Language: English
• Published: 01-03-1993
• ISSN: 1051-8223
• DOI: 10.1109/77.233600

GdBa(2)Cu(3)O(7), which has very similar properties to YBa(2)Cu(3)O(7) but appears to be more tolerant of processing conditions, is studied. Thin films have been prepared by inverted cylindrical magnetron sputtering on MgO single crystals and routinely give transition temperatures above 92 K and critical currents above 10(6) A/cm(-2) at 77 K. Films with areas exceeding 12 cm(2) have been fabricated on 0.5-mm-thick substrates. Structural and compositional studies show a high degree of film perfection. Measurements of surface resistance, using a cavity endwall replacement technique at 60 GHz, give values < 20 mOmicron at 77 K (uncorrected for film thickness. typically 0.4-0.5 mum) and suspended substrate stripline resonators give < e1 > Q < /e1 > values over an order of magnitude larger than the corresponding gold resonator. A 2% 4-GHz filter has been realized in microstrip with a minimum insertion loss below 0.6 dB