Comparative investigation of the ball milling role against hand grinding on microstructure, transport and pinning properties of Y3Ba5Cu8O18 (+/-) (delta) and YBa2Cu3O7-delta

We report a comparative investigation between the two high temperature superconductor materials YBa2Cu3O7-delta (Y-123) and Y3Ba5Cu8O18 (+/- delta) (Y-358) by probing the impact of high-energy ball milling (HEBM) technique on the microstructure, transport properties and pinning capacities. Products were elaborated via the solid-state reaction (SSR) by employing two kinds of milling; hand grinding in agate mortar and HEBM in a planetary crusher. The morphology, chemical compositions and crystal structure of all produced products were explored by scanning electron microscope (SEM) along with EDXS and X-ray diffraction (XRD). The superconductivity was confirmed by electrical resistivity measurements. The transport and intra-granular critical currents densities were estimated through the current-voltage and magnetization measurements. The planetary HEBM process generates nano-sized Y-deficient Y-123 and nano-sized Y-deficient Y-358 entities dispersed in the Y-123 and Y-358 matrix, respectively. The Y-358 sample milled by HEBM exhibits the best pinning capacity. This result can be ascribed to the occurrence of more disorder in Y-358 compound compared to Y-123 one.