Effect of second-phase precipitates and deposition temperature on the hysteretic losses in CVD-prepared Nb3Ge

Abstract
Hysteretic losses have been measured on a large number of Nb3Ge samples prepared by the chemical vapor deposition process. These measurements were performed as a function of induced current and temperature on samples which contained differing amounts of second‐phase material, Nb5Ge3. It was found that very low 50‐Hz losses, on the order of 20 μW/cm2 at 500 rms A/cm and at temperatures of up to 12 K, could be attained in as‐deposited material. An apparent correlation between the critical current density and the Nb5Ge3 content was observed, which suggested that enhanced pinning due to the second‐phase precipitates was responsible for these low losses.