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_delta (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 Hc(2) 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 J(cinter)(0) increases from 1.18 kA/cm(2) for the pristine sample to 5.10 kA/cm(2) 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.

Automated summary

The study prepared YBCO samples with 0.1 wt% artificial BTO and WO3 nanoparticles via solid-state reaction route, analyzed their phase purity and microstructure using X-ray diffraction and scanning electron microscopy. The results showed that the addition of BTO and WO3 nanoparticles improved superconducting performance, increasing Hc(2) to 3.4 T and J(cinter)(0) to 5.10 kA/cm(2).