Critical Current Density and Flux Pinning in Nb3Ge

High self‐field critical current densities, J_c, of the order of 10⁶ A/cm² between 4 and 14 K have been reported for chemical vapor deposited (CVD) films of ${\mathrm{Nb}}_3\mathrm{Ge}$ . Our results of J_c measurements in a wide field range and film composition analyses suggest that high values of J_c are due primarily to flux pinning on dispersed tetragonal (σ) phase. Single phase (A15) ${\mathrm{Nb}}_3\mathrm{Ge}$ samples exhibited lower J_c of the order of 10⁴ to 10⁵ A/cm². The ac loss measurements corroborate the proposed interpretation.