Irreversible magnetostriction and magnetization of superconducting 2H-NbSe2 single crystals in a peak-effect regime

Magnetostriction measurements in the mixed state of superconducting 2H-NbSe2 single crystals under in-plane magnetic fields 0-12 T have revealed a peak on the magnetostriction versus magnetic field dependences in the vicinity of the upper critical field H-c2. The peak value of the longitudinal magnetostriction is higher by more than an order of magnitude in comparison with that of the transverse magnetostriction when measured along the hexagonal axis. Analysis of the measured field dependences of the magnetostriction and magnetization of 2H-NbSe2 allows one to relate the observed peculiarities of magnetostriction with the loss of order in the lattice of Abrikosov vortices, which occurs by a first-order phase transition. (C) 2002 American Institute of Physics.