Absence of mode-locking resonance for driven vortices in a thin amorphous MoxGe1−x film

Abstract

We present measurements of the mode-locking (ML) resonance for the thin amorphous MoxGe1−x film with weak pinning. In contrast to the thick film, where the clear ML resonance indicative of driven vortex lattices is observed over a wide temperature T and field B range, any sign of ML is not detected for the thin film down to below 1 K The results suggest that the vortex lattice for the thin film may be unstable against small pinning. We construct the vortex phase diagram in the B − T plane, which consists of disordered solid phase and large liquid phase.