Pinning effects in two-band superconductors

Recently, new high-temperature superconductors have been discovered. One such material, magnesium diboride, is an ideal candidate for superconducting technology due to its high critical temperature (39 K), high critical current, and relative inexpensiveness. Numerical simulations of vortex dynamics and vortex pinning in such materials can help investigate material properties that can be utilized in superconducting technology. Unfortunately, magnesium diboride comes with many odd properties such as multiple superconducting bands rendering previous numerical models of superconductivity unable to fully describe vortex behaviors. It is well known in one-band superconductors that impurities can pin vortices and thus reduce the resistance. Here, we propose a modified Ginzburg-Landau model to describe a two-band superconductor with normal inclusions. The new model is used to investigate the effects of vortex pinning in magnesium diboride with regards to passing a resistance-free current through the superconducting sample.