High temperature and low field regime vortex phase diagram of in-situ prepared stainless steel sheathed MgB2 tapes☆

Abstract A magnetic field-temperature vortex phase diagram has been proposed for MgB 2 on the basis of magnetoresistance studies performed on an in-situ prepared stainless steel sheathed MgB 2 tapes. Thermally activated flux flow (TAFF) behavior is analyzed using Arrhenius relation. Low dissipative part of magnetoresistance with temperature is well described by vortex glass theory. Above critical region, the resistive behavior is influenced by fluctuation conductivity. In addition, a considerable vortex liquid region below H C2 is also observed but TAFF region is found to be quite narrow.