Magnetism and ferromagnetic loss in Ni-W textured substrates for coated conductors

A study has been conducted on the magnetic properties of a series of biaxially textured Ni_1-xW_x materials with compositions x=0,3,5,6, and 9 at.% W. These materials are important as substrates for "RABiTS"-type coated conductors that incorporate high temperature superconductors for current transport. The quasi-static dc and ac hysteretic loss W was determined to support estimates of the ferromagnetic contribution to the overall ac loss in potential ac applications. The alloys were prepared by either vacuum casting or powder metallurgy methods, and the hysteretic loss tended to be lower in materials that were recrystallized at higher temperatures. Some samples were progressively deformed (0.4% bending strain) to simulate winding operations; this increased the hysteretic loss, as did sample cutting operations that create localized damage. In ac magnetization measurements, the effects of ac frequency and dc bias field on the ferromagnetic loss were determined.