Development of textured substrates with low magnetism

In order to develop a Ni-alloy/Ni-alloy clad substrate with low magnetism and high strength, Ni–W alloy substrates with 3at.%, 5at.% and 7at.%W content were investigated. All Ni–W substrates exhibit a sharp cube ({100}〈001〉) texture and the epitaxial CeO2 buffer layer was successfully deposited on the Ni–W substrates by electron-beam (EB) evaporation. The saturated magnetization (Ms) for Ni–3at.%W and Ni–7at.%W alloy at 77K are 0.41 and 0.12T, respectively. Ms decreases inversely proportional to the W content of Ni–W substrate and at 9at.%W content Ms was estimated to become zero. The 0.2% proof stress for textured Ni–3at.%W and Ni–7at.%W substrate at room temperature is 150 and 210MPa, respectively. These are four to five times higher than that of textured pure Ni substrate. Critical current of a short sample which was formed YBCO layer with Δϕ=5.4° by pulse laser deposition (PLD) on EB-CeO2/PLD-YSZ/EB-CeO2/Ni–3at.%W substrate was 140A/cm-width. Moreover, a sample which was formed YBCO by metal-organic deposition (MOD) on Ni–5at.%W substrate by the collaboration with Superconductivity Research Laboratory (SRL) showed critical current of 310A/cm-width. These results indicate that the Ni-alloy clad substrate with low magnetism and high strength is promising.