Development of long YBCO coated conductors by multiple-stage CVD

Abstract We have developed YBCO coated conductors by Multiple-Stage Chemical Vapor Deposition (MS-CVD) technique, which can make YBCO layer with high deposition rate and easy to scale up by increasing the number of reactors. We confirmed that the high speed production by the twelve-stage CVD equipment, which was designed to scale up CVD process, did not affect the property of YBCO coated conductors and that the YBCO coated conductors with I c of 100 A-class could be fabricated by the high speed production of 10 m/h. In order to demonstrate the advantage of the MS-CVD technique for longer YBCO coated conductors, we have also fabricated the 92-m-long YBCO conductor on an IBAD substrate. The YBCO conductor was fabricated with a tape moving at the speed of 25 m/h and was deposited several times to control the thickness of the YBCO films. The end-to-end I c of the 92-m-long YBCO tape was measured by criterion of 1 μV/cm and was 96 A ( J c of 1.9 MA/cm 2 ). We have successfully realized the fabrication of the YBCO coated conductor with the practical properties of 100 A-class in I c and 100 m-class in length. Recently, we have also obtained high I c of 227 A ( J c of 2.3 MA/cm 2 ) in a short sample of a YBCO conductor on IBAD substrates by optimization of the fabrication process.