Superconducting Hc-Jc and Tc Measurements in the Nb–Ti–N, Nb–Hf–N, and Nb–V–N Ternary Systems

Abstract

Superconducting critical fields, current densities and temperatures have been measured as a function of composition in the Nb–Ti–N, Nb–Hf–N and Nb–V–N ternary systems. In the Nb–Ti–N system the upper critical fields increase sharply and monotonically with increasing NbN concentration to over 130 kOe at about 90 mole % NbN. In the Nb–Hf–N system the highest upper critical-field value observed was 130 kOe for the composition Nb0.92Hf0.08N. In the Nb–Hf–N system the Tc increases monotonically with NbN concentration, in the Nb–Ti–N system a maximum in Tc exists at about 65 mole % NbN and in the Nb–V–N system a broad minimum exists between 30 and 50 mole % VN.