Spectrum analysis of voltage noise of moving vortex lattice and dynamic phase transition

Abstract

Using Langevin molecular dynamics method, we have studied the voltage noise spectrum generated by current-driven vortices as a function of the magnetic field an d current. It is found that the broad band noise (BBN) at low frequencies decrea ses with increasing magnetic field, it decreases at the magnetic field near th e vortex dynamic transition field FP， and the Lorentze narrow ba nd noise (NBN) at high frequencies appears. As the magnetic field increases near the melt ing field Fm, the NBN peak goes up and shifts towards higher freq uencies. In the elastic motion region of vortices with strong driving currents, NBN exhib its the washboard-like shape. This behavior arises from the periodic modulation of the translational velocity of vortices, suggesting that there is a Bragg gla ss phase with the translation order in the vortex lattices of the layered superc onductors.