Magnetization and critical current of high-temperature superconductors with artificial pinning centers

摘要

We present new data on magnetization at T = 4.2 and 77 K for polycrystalline high-temperature superconductors of the Bi2Sr2Ca2Cu3O10 + delta system containing various amounts of nanodimensional inclusions of tantalum carbide, niobium carbide, or niobium nitride. The introduction of these nanoparticles (less than or equal to30 nm in size) leads to an increase in the magnetization and the critical current density. It is established for the first time that the dependence of the normalized critical current on the bulk concentration of indicated dopants is described by the same universal curve. The interval of the optimum dopant concentrations is found, in which the additives lead to the maximum increase in the critical current density. (C) 2005 Pleiades Publishing, Inc.