Interaction between superconductor and ferromagnetic domains in iron sheath: Peak effect in MgB_2/Fe wires

摘要

Interaction between the superconductor and ferromagnet in MgB_2/Fe wires results in either a plateau or a peak effect in the field dependence of transport critical current, I_c(H). This is in addition to magnetic shielding of external field. Current theoretical models cannot account for the observed peak effect in I_c(H). This letter shows that the theoretical explanation of the peak effect should be sought in terms of interaction between superconductor and magnetic domain structure, obtained after the remagnetization of the iron sheath by the self-field of the current. There is a minimum value of critical current, below which the remagnetization of the iron sheath and peak effect in I_c(H) are not observed.