Anisotropies in the critical currents of NbN films

The cubic interstitial nitride of niobium has been of interest recently because of its high transition temperature (≃ 16K). It has been known that NbN in a bulk state shows a poor critical current carrying capacity of 10³A/cm². However, it was found that NbN films prepared by reactive sputtering exhibit much larger Jcand critical field Hc2as compared to those of the bulk. In the present paper, we report the anisotropies in the critical currents of NbN films prepared by reactive sputtering. The effects of the substrate and annealing on the anisotropies are also investigated. For additional details, see Digests of the 1972 Intermag Conference (available from IEEE Headquarters).