Pinning force scaling of electrospun Bi-2212 nanowire networks

Koblischka, Michael R.; Gokhfeld, Denis; Chang, Crosby; Hauet, Thomas; Hartmann, Uwe SOLID STATE COMMUNICATIONS, 264 16-18; 10.1016/j.ssc.2017.07.002 SEP 2017

Flux pinning forces were determined on different network samples of superconducting ${Bi}_{2} {Sr}_{2} {CaCu}_{2} O_{8}$ (Bi-2212) nanowires prepared by the electrospinning technique. We employed magnetization data determined by SQUID magnetometry in a wide temperature range 10 K $< T <$ 35 K, where a strong superconducting signal prevails. The scaling analysis of the pinning forces was applied to interprete the data obtained. Both pure and Li-doped Bi2212 nanowire networks exhibit a peak position of $h_{0} \sim$ 0.11, which is smaller than the expected value of $h_{0} =$ 0.2 indicating flux pinning at grain boundaries or extended defects. For the flowing currents through such a network, the crystallographic anisotropy and the percolation play an important role, resulting in reduced peak positions as compared to bulk samples.