Enhanced Critical Current Density of FeF2 Added YBa2Cu3O7−δ

Abstract

The effect of nanosized FeF2 (∼120 nm) addition on the critical current density, Jc, of YBa2Cu3O7−δ was studied. YBa2Cu3O7−δ superconductor was prepared by the solid-state reaction method with addition of 0 to 0.10 wt% FeF2 additions. The magnetization critical current density, Jcm (at 77 K), was estimated from the extended Bean model by using vibrating sample magnetometer (VSM) measurements. The transport critical current density, Jct, was measured using the four-point probe method with the 1 µV/cm criterion. The onset transition temperature, \(T_{\mathrm{c}\mbox{-}\mathrm{onset}}\) showed a maximal value at 92 K for 0 to 0.03 wt% additions. Jc increased with FeF2 addition up to 0.03 wt%. Addition of FeF2 of more than 0.03 wt% suppressed \(T_{\mathrm{c}\mbox{-}\mathrm{onset}}\) and Jc. The inter-grain current density was enhanced by two orders of magnitude on 0.03 wt% FeF2 addition. In addition to the condensation energy associated with their core, the full vortex magnetic energy by addition of nanosized FeF2 enhanced Jc in the system.