Evidence for possible interaction between CDW and magnetic vortices in 2H-NbSe₂ : comparison with 2H-NbS₂

Abstract

We have performed vibrating reed (f~1 kHz) and ac susceptibility (f~800 kHz, i.e. RF penetration depth) measurements on superconducting 2H-NbSe2 and 2H-NbS2 in magnetic fields. For NbSe2, a low temperature dissipation peak is correlated with a dip in vibrating reed resonant frequency and peak in ac susceptibility, signifying softening of the flux line lattice ; these features are not observed in NbS2. We suggest that the softening of the FLL is due to an interaction with the CDW, which does not occur in NbS2