Response of a superconductor NbSe2 flake to magnetic field detected with small tunnel junctions

We have experimentally studied response of a superconductor NbSe2 flake to perpendicular magnetic fields using small tunnel junctions. The NbSe2 film (lateral size similar to several mu m, thickness similar to 50 nm) was obtained using the mechanical exfoliation of a bulk crystal and was transfered on top of predefined Au electrodes, forming an Au/NbSe2/Au double SIN tunnel junction system. At 4.2 K, between the lower and upper critical fields (H-C1 and H-C2), the voltage of the Au/NbSe2/Au structure under constant current of 1 mu A exhibited random-telegraph-noise-like fluctuations as a function of the magnetic field which was applied perpendicular to the NbSe2 flake. The origin of the voltage fluctuations is discussed.