Vortex states just below the vortex-glass phase probed by voltage noise

We measure the current-induced voltage noise in various fields H to study the vortex states of a thick amorphous MoxSi1-x film. We focus on the field region between the Meissner phase and the vortex-glass (VG) phase, where vortex states have not yet been clarified. Noise S-V is largest in the Meissner phase (H < H-c1). With increasing H(> H-c1), S-V falls near or below the background level. With further increasing H, S-V starts to rise at certain field H-0, taking a broad peak in the VG phase, and falls again below the background level at a VG-to-liquid transition H-g. We interpret H-0 as a characteristic field around which VG order starts to form. We find that in the temperature range studied the field region (H-c1 < H < H-0) grows monotonically upon cooling. (C) 2003 Elsevier Science B.V. All rights reserved.