FLUX-LINE RESPONSE IN 2H-NBSE2 INVESTIGATED BY MEANS OF THE VIBRATINGSUPERCONDUCTOR METHOD

We measure transverse AC losses in the low- and high-amplitude regime of 2H-NbSe2 single crystals using vibrating superconductor methods. Th e measurements are sensitive to small deviations of the critical state . The data constitute evidence for a peak effect of the critical curre nt as a function of the temperature in this compound. We construct in the H-T phase diagram the ''peak-effect'' line which is supposed to ma rk an abrupt cross-over in the vortex-pinning regime.