Flow Noise of Driven Vortex Matter inAmorphous Superconducting Films

摘要

Voltage noise SvW generated by current-driven vortices is studied as a function offlow voltage V and magnetic field for a superconducting amorphous MorGei.x film. For high V(or velocity) in the flux-flow state, S_v at low frequency (f=100 Hz) exhibits a sharp peak justbelow a peak field of the critical current. For low V in the plastic-flow state, an additional broadpeak of S_vappears at lower field. Possible origin responsible for large flow noise is discussed.We show that for moderate V, Sv clearly detects the structural phase transition of vortex matter.