Critical fields and defect structure of vanadium deformed at 4.2 K

The variation of the second critical field Hc2 in coarse-grain vanadium due to torsional strain at 4.2 K is studied. In the region of elastic deformation, a slight increase in the value of Hc2 is observed. Beyond the yield point, the strain in a vanadium sample is nonuniform. In the regions of localized plastic flow (twin boundaries or large dislocation pile-ups), Hc2 and Tc increase due to an increase in the electron–phonon interaction constant.