YBCO polycrystal co-added with BaTiO3 and WO3 nanoparticles: Fluctuation induced conductivity and pseudogap studies

Abstract

We report the effect of the addition of BaTiO3 and WO3 nanoparticles on the pseudogap and excess conductivity of YBCO polycrystal. The excess conductivity analysis showed that the experimental data of pure and sample added with low amount of WO3 and BaTiO3 were perfectly described by the 2D Maki-Thompson (MT) and 3D Aslamazov-Larkin (AL) models. A sharp decrease in excess conductivity was obtained for samples added with high amount of nanoparticles where the analysis indicated the presence of the AL contribution and Lawrence-Doniach (LD) models. The pseudogap (PG) results showed that the value of Tpair (the temperature at which local pairs are transformed from strongly bound bosons into the fluctuating Cooper pairs) increased from around 117 K for the pure sample to around 187 K for sample co-added with low amount of nanoparticles. The pseudogap Δ*(TG) reduced from 230.9 K (for pure sample) to 223.4 K (for added sample).