Critical current and topology of the supercooled vortex state in NbSe2

Abstract

We study the behavior of the critical current, Ic(H,T), of pure and Fe doped NbSe2 crystals in the denominated disordered vortex region, limited by the critical field Hc2(T) and the field Hp(T) at which the peak effect in Ic(H,T) is detected. The critical current follows an individual pinning response as demonstrated by its field independent universal function of the superfluid density. Transport measurements combined with Bitter decorations show no evidence of the existence of an amorphous phase in the high temperature region.