Effect of Nanoparticles with Different Size on the Transport Critical Current Density of Bi_(1.6)Pb_(0.4)Sr_2Ca_2Cu_3O_(10) Superconductor

摘要

In general, for a nanoparticle to act as a pinning center, the size L should be larger than the coherence length, x and smaller than the penetration depth, λ. In this paper we compared the effects of different nano-sized particles (where x< L< λ), MgO (20 and 40 nm) versus ZnO (6 and 30 nm) on the transport critical current density of the Bi-based superconductors. All nanoparticle added samples showed higher transport critical current density, J_c compared with the non-added samples. In Bi_(1.6)Pb_(0.4)Sr_2Ca_2Cu_3O_(10)(MgO)_x, the 20 nm MgO added samples showed a higher Jc compared with the 40 nm MgO added samples. The 6 nm ZnO added samples also showed higher J_c compared to the 30 nm added samples. These results showed that the size of flux pinning center is important in enhancing Jc and particle with size closer to the coherence length showed higher transport critical current density.