抄録
Offer Organization: Japan Society for the Promotion of Science, System Name: Grants-in-Aid for Scientific Research, Category: Grant-in-Aid for Scientific Research (B), Fund Type: -, Overall Grant Amount: - (direct: 14700000, indirect: 4410000)
We have developed a measurement system for a mode-locking resonance with pulsed currents that generate much less heat (by three orders of magnitude) than the previous one, which enables to detect the flow of fast driven vortex lattices. By employing it at low temperatures down to 0.05 K, we successfully observe the dynamic quantum melting of driven lattice in the limit of zero pinning. Thus, we complete static vortex phase diagrams at nearly zero temperature as a function of applied field, namely, the phase diagrams of the field-induced quantum phase transition simultaneously in the absence and presence of pinning. Also, we have performed studies on the reversible-to-irreversible flow transition (RIT) and obtained the following new results: We acquire information on the vortex configuration in the vicinity of RIT. Also, we observe the critical behavior of RIT in the translational motion system where only the local ac shear due to strong random pinning is present.