Superconductivity at 100—Where we’ve been and Where we’re Going
a1 National High Magnetic Field Laboratory, Tallahassee, FL 32310, USA; firstname.lastname@example.org
a2 Department of Physics, Old Dominion University, Norfolk, VA 23529, USA; email@example.com
This article gives a brief comparative overview of the upper critical fields Hc2(T)—the magnetic fields above which superconductivity disappears—of MgB2- and Fe-based superconductors. We discuss manifestations of multiband superconductivity, Pauli pair-breaking, and pairing symmetry in the shapes of Hc2(T) curves, and the ways of tuning Hc2(T) by doping and by impurity scattering. We show that the effective route to high Hc2 is by disordering in MgB2 and by doping-assisted tuning of the Fermi surface in Fe-based superconductors. These effects allow extremely high Hc2 values in both material classes that well exceed those found in Nb-based superconductors, opening up new opportunities for high-field applications.