Fulx-pinning mechanism and activation energy in malic acid-doped MgB2

• Main Authors: SR Ghorbani, M Bashi, A Broghani
• Format: Article
• Language: English
• Published: Isfahan University of Technology 2010-09-01
• Series: Iranian Journal of Physics Research
• Subjects: critical current density; fulx-pinning mechanism; activation energy superconductor MgB2
• Online Access: http://ijpr.iut.ac.ir/browse.php?a_code=A-10-1-464&slc_lang=en&sid=1

Fulx-pinning mechanism and activation energy of MgB2 doped with 10 wt % malic- acid has been investigated by measurement of critical current density and resistivity as a function of magnetic fields and temperatures. The field dependence of the critical current density, Jc(B), was analyzed within the collective pinning model. A crossover field, Bsb, from the single vortex to the small vortex bundle-pinning regime was observed. For sintered sample, the temperature dependence of Bsb(T) at low temperature is in good agreement with the δℓ pinning mechanism, i.e., pinning associated with charge-carrier mean free path fluctuation. The activation energy was decreased linearly by increasing magnetic field.