Intergranular properties of polycrystalline YBa2Cu3O7−δ superconductor added with nanoparticles of WO3 and BaTiO3 as artificial pinning centers

Pure (x = 0.0 wt%) superconducting YBa2Cu3O7−δ (YBCO) sample and added YBCO sample with 0.1 wt% artificial barium titanate (BTO) and 0.1 wt% tungsten trioxide (WO3) nanoparticles were prepared using the solid-state reaction route. Phase purity was analyzed via the X-rays diffraction technique. Scanning electron microscopy showed a high density of isolated W-rich secondary phases embedded within the YBCO added sample. Furthermore, both WO3 and BTO nanoparticles tend to reside at the grain boundaries and play the role of bridges connecting the YBCO superconducting granules. Quantitative analysis performed on the areas where nanosized entities induced by BTO and WO3 phases was evidenced by EDX analysis equipped with SEM instrument. The values of Hc2 increased from 1.6 T for pristine to 3.4 T for BTO/WO3 added samples. The superconducting parameters determined by AC susceptibility measurements also showed an improvement with WO3 and BTO nanoparticles co-addition. The value of Jcinter(0) increases from 1.18 kA/cm2 for the pristine sample to 5.10 kA/cm2 for BTO/WO3 co-added sample. Hence, the incorporation of artificial BTO and WO3 nanoparticles into the YBCO superconducting phase could be a useful way to make such compounds available in practical applications.