Flux pinning and inhomogeneity in magnetic nanoparticle doped MgB2/Fe wires

Authors

Nikolina Novosel, University of Zagreb
Damir Pajic, University of Zagreb
Mislav Mustapic, University of WollongongFollow
Emil Babic, University of Zagreb
Andrey Shcherbakov, University of WollongongFollow
Josip Horvat, University of WollongongFollow
Zeljko Skoko, University of Zagreb
Kreso Zadro, University of Zagreb

RIS ID

35247

Publication Details

Novosel, N., Pajic, D., Mustapic, M., Babic, E., Shcherbakov, A., Horvat, J., Skoko, Z. Zadro, K. (2010). Flux pinning and inhomogeneity in magnetic nanoparticle doped MgB₂/Fe wires. In 9th European Conference on Applied Superconductivity (EUCAS 09), 13-17 Sep 2009, Dresden, German. Journal of Physics: Conference Series, 234 (part 2), 022027-1-022027-7.

Abstract

The effects of magnetic nanoparticle doping on superconductivity of MgB₂/Fe wires have been investigated. Fe₂B and SiO₂-coated Fe₂B particles with average diameters 80 and 150 nm, respectively, were used as dopands. MgB₂ wires with different nanoparticle contents (0, 3, 7.5, 12 wt.%) were sintered at temperature 750°C. The magnetoresistivity and critical current density J_c of wires were measured in the temperature range 2–40 K in magnetic field B ≤ 16 T. Both transport and magnetic Jc were determined. Superconducting transition temperature T_c of doped wires decreases quite rapidly with doping level (~ 0.5 K per wt.%). This results in the reduction of the irreversibility fields B_irr(T) and critical current densities J_c(B,T) in doped samples (both at low (5 K) and high temperatures (20 K)). Common scaling of J_c(B,T) curves for doped and undoped wires indicates that the main mechanism of flux pinning is the same in both types of samples. Rather curved Kramer's plots for J_c of doped wires imply considerable inhomogeneity.