Relaxation and pinning in spark-plasma sintered MgB.sub.2./sub. superconductor

0458752 - FZÚ 2017 RIV GB eng J - Journal Article
Jirsa, Miloš - Rameš, Michal - Koblischka, M.R. - Koblischka-Veneva, A. - Berger, K. - Douine, B.
Relaxation and pinning in spark-plasma sintered MgB₂ superconductor.
Superconductor Science and Technology. Roč. 29, č. 2 (2016), 1-7, č. článku 025006. ISSN 0953-2048. E-ISSN 1361-6668
Institutional support: RVO:68378271
Keywords : bulk MgB₂ superconductor * magnetic properties * magnetic relaxation * critical currents * pinning force density
Subject RIV: BM - Solid Matter Physics ; Magnetism
Impact factor: 2.878, year: 2016

The model of thermally activated relaxation developed and successfully tested on high-T c superconductors (Jirsa et al 2004 Phys. Rev. B 70 0245251) was applied to magnetic data of a bulk spark-plasma sintered MgB2 sample to elucidate its magnetic relaxation behavior. MgB2 and the related borides form a superconductor class lying between classical and high-T c superconductors. In accord with this classification, the relaxation phenomena were found to be about ten times weaker than in cuprates. Vortex pinning analyzed in terms of the field dependence of the pinning force density indicates a combined pinning by normal point-like defects and by grain surfaces. An additional mode of pinning at rather high magnetic fields (of still unknown origin) was observed.

Permanent Link: http://hdl.handle.net/11104/0258995