Continuous tape coating by thermal evaporation

Among the various coating techniques, thermal evaporation currently allows the highest YBCO volume deposition rates because of its large area capability. This "simultaneous large area deposition" capability translates into long tape lengths when the deposition area is densely filled up with metal tape. On short rolling-assisted biaxially textured substrate samples thermal evaporation has already established critical current densities in excess of 1 MA/cm² at 77 K, with very promising performance in magnetic fields. Recently, the deposition technique has been scaled up using a multiturn tape winder giving a simultaneously coatable length of about 4 m of 1-cm-wide tape. The reel-to-reel tape deposition system is designed for long term continuous operation based on in-situ refillable evaporation sources and controlled using feedback from atomic absorption spectroscopy measurements in the vapor phase. Here, the authors present results on the first coated conductor tape continuously fabricated by this technique.