Flux-pinning mechanism in silicone-oil doped MgB2: Evidence for charge-carrier mean free path fluctuation pinning

Authors

Shaban R. Ghorbani, University of WollongongFollow
Xiaolin Wang, University of WollongongFollow
S X. Dou, University of WollongongFollow
Sung-Ik Lee, Center for Superconductivity, Sogang University, Korea
Md S. Hossain, University of WollongongFollow

RIS ID

24916

Publication Details

Ghorbani, SR, Wang, X, Dou, SX, Lee, S & Hossain, M (2008), Flux-pinning mechanism in silicone-oil doped MgB2: Evidence for charge-carrier mean free path fluctuation pinning, Physical Review B (Condensed Matter and Materials Physics), 78(18), pp. 184502-1-184502-5.

Abstract

Flux-pinning mechanism of MgB₂ doped with 10 wt % silicone-oil sintered at low and high temperatures has been investigated by magnetic measurements. The field dependence of the critical current density, j_c(B), was analysed within the collective pinning model. A crossover field, B_sb, from the single vortex to the small vortex bundle-pinning regime was observed. For both types of sintered samples, the temperature dependence of B_sb(T) at low temperature is in good agreement with the δl pinning mechanism, i.e., pinning associated with charge-carrier mean free path fluctuation. At temperatures close to the critical temperature, however, there is evidence for δT_c pinning, which is associated with spatial fluctuations of the transition temperature. These results provide strong evidence that the liquid precursor, silicone oil, produces very small pinning centers and enhances the j_c(B).

Grant Number

ARC/DP0770205

Additional Grant Number

http://purl.org/au-research/grants/ARC/DP0770205