HIGH-FIELD MAGNETORESISTANCE OSCILLATIONS IN NBSE3

We report on magnetoresistance experiments performed on NbSe3 with pul sed magnetic fields (i) up to 37 teslas in the temperature range from 2K to 24K and (ii) up to 52 teslas at a temperature of 2K. In addition to the low field oscillations associated with the Landau levels n gre ater-than-or-equal-to 1, a huge oscillation is observed at 38 teslas i n the ultra quantum limit. The whole set of experimental data are well accounted for by the Shubnikov-de Haas (SDH) model : the 38 teslas os cillation is in agreement with the predicted value for the 0+ Landau l evel, taking into account the Zeeman splitting. Moreover, the analysis of the temperature dependence of the SDH oscillation amplitude record ed during the 37 teslas experiments yield consistent values for both t he cyclotron mass and the Dingle temperature.