Epitaxial YBCO(F) films directly deposited on sapphire and its microwave properties

✍ Scribed by Rosa Young; Kwo Young; John D Budai; Jon S Martens; Gene Venturini; Marshall Muller; Stanford Ovshinsky

• Publisher: Elsevier Science
• Year: 1992
• Tongue: English
• Weight: 379 KB
• Volume: 32
• Category: Article
• ISSN: 0011-2275
• DOI: 10.1016/0011-2275(92)90235-3

✦ Synopsis

High quality epitaxial YBa2Cu307_8(F) films were grown directly on r-plane (1102) sapphire by a pulsed laser deposition technique using a multiphase fluorinated target. X-ray diffraction data showed that the film is highly c-axis oriented and in-plane aligned. The c-axis and in-plane mosaic spread are 1.1 ° and 2.4 °, respectively. The film has aTc(R=0) of 89K with a transition width less than 0.25K. The microwave surface resistance Rs measured by a con-focal resonator configuration is 56m~ at 94.1 GHz at 77K which is the best reported value for a YBCO film on sapphire. The magnetization critical current density is as high as 3x107 A/cm 2 at 5K and 2x106 A/cm 2 at 77K. A bandpass filter which is centered at 8.1 GHz is fabricated. A very low insertion loss (<0.1dB) is observed within the whole passband.