The preparation of cubic NbN films by reactive dc magnetron sputtering is described. These superconductive films are deposited at a sufficiently low temperature (<90 °C) that photoresist liftoff techniques and can be used in fabricating Josephson junctions. The superconducting transition temperature has been measured as a function of gas composition and pressure. It reaches a maximum of 14.2 K at 15% N2–85% Ar and 1.06 Pa total pressure. The resistivity ratio of these films is close to unity. Structural studies by transmission electron microscopy and electron diffraction show that films 100-nm thick or less are randomly oriented, and noncolumnar with a crystallite diameter of 5 nm and a lattice parameter of 4.46 Å, which is significantly higher than the bulk value for cubic NbN. The films are dense with void diameters no larger than 0.7 nm. Films 300-400 nm thick show a small degree of texturing in x-ray studies with a Read camera. Auger analysis shows a monotonic increase in the N/Nb ratio with increase in the N2/Ar ratio in the sputtering ambient up to 30% N2. From 30% to 50% N2 in the sputtering mixture the N/Nb ratio is constant. Small amounts of carbon impurity are found in all films.
The increasingly broad range of applications for the Permalloy family of magnetic materials has made them the object of intense and continuing study over the years. In this review, four main types of magnetic anisotropy are first discussed. These are the magnetocrystalline, magnetostrictive, thermomagnetic, and slip-induced anisotropies. It is pointed out that control of these anisotropies through composition selection and judicious processing procedures is the key to attainment of high initial permeability and squareness in the Ni–Fe–Mo–Cu system. Specifically, while zero anisotropy from all sources is the goal for high initial permeability, introduction of a nonzero anisotropy has proven effective in obtaining good squareness. The influence of metallurgical factors, in particular the role of crystallographic texture, is discussed.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.