The dHvA effect experiments on Nb have been performed in low fields down to Hc2 using a standard field modulation method. The signal amplitude becomes much smaller below Hc3 than that expected from a straight extension of the Dingle plot from the higher fields and is below the noise level around and below Hc2. The rapid decrease of the amplitude below Hc3 is simply understood as arising from the screening of the modulation field and is expected to be observed for other homogeneous type-II superconductors. The present observation is inconsistent with those reported for materials such as NbSe2, where the same or comparable amplitudes to those in the normal state are detected below Hc2 by the field modulation method.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Energy Engineering and Power Technology
- Electrical and Electronic Engineering