Sample-size dependence of the magnetic critical current density in MgB2 superconductors

سازوکار میخکوبش و انرژی فعال سازی در ابررسانای MgB2 آلاییده به مالیک اسید

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 bun...

پیشرفتهای اخیر در زمینه ساخت سیم و نوار ابررسانای MgB2

 MgB2 wire and tape were prepared using the powder in tube and reaction in-situ technique. All samples were characterized using the XRD, SEM, TEM, as well as transport and magnetic measurements. High transport and magnetic critical current density values have been obtained for metal-clad wires and tapes. Different sheath materials have been examined, but Fe appears to be the best sheath for MgB...

Effect of sample size on the magnetic critical current density in nano-SiC doped MgB2 superconductors

Effects of the sintering temperature on the flux-pinning mechanism and the activation energy of malic-acid doped MgB2

  The flux-pinning mechanism and activation energy of 10 wt % malic acid-doped MgB2 were investigated by measuring of the critical current density and resistivity as a function of magnetic field and temperature. A crossover field, Bsb, was observed from the single vortex to the small vortex bundle pinning regime. For the sintered sample, the temperature dependence of Bsb(T) at low temperature i...

Transport and magnetic critical current in superconducting MgB2 wires

Direct comparison of the magnetic and transport critical current density (Jc) for the same pieces of copper-sheathed MgB2 wires shows a large discrepancy in magnitude and field dependence of the two. The value of magnetic Jc can differ from the value of transport Jc by a factor of 10 or more. This discrepancy does not occur merely because of the difference in the voltage at which the magnetic a...