CONICET | Buscador de Institutos y Recursos Humanos

AC dynamics, plastic motion and vortex matter reorganization D.Pérez Daroca, G. Pasquini, G. Lozano and V. Bekeris Departamento de Física, Universidad de Buenos Aires; IFIBA, CONICET, Argentina Among the broad and complex phenomenology observed in vortex matter one of the most surprising behaviors occurs in the neighborhood of the order-disorder (O-D) transition, where the system evolves from a quasi-ordered Bragg glass (BG) to a disordered phase with proliferation of topological defects. Metastability, history effects and a very complex dynamics are common facts observed in this region both in low and in high Tc materials. In NbSe2 single crystals an enlarged crossing phase boundary between the ordered and disordered phases has been reported and corroborated for our group[1]. In this work[2], we study experimentally and numerically[3] the vortex matter reorganization driven by oscillatory forces near the plastic depinning transition. We show that the in this intermediate region the system can be taken to configurations that are tagged by the shaking parameters but keep no trace of the initial conditions. In our experiments, the periodic drive is induced by ac magnetic shaking fields and the overall order of the resulting configuration is determined by non invasive ac susceptibility measurements. With a model of interacting particles driven over random landscapes, we perform molecular dynamics simulations that reveal the nature of the shaking dynamics as fluctuating states similar to those predicted for other interacting particle systems. [1] G. Pasquini, D. Pérez Daroca, C. Chiliotte, G. Lozano and V. Bekeris; Phy. Rev. Lett. 100, 247003 (2008). [2] D. Pérez Daroca, G. Pasquini, LG. Lozano and V. Bekeris, submitted to Phys. Rev. B (R) (2011). [3] D. Pérez Daroca, G. Pasquini, LG. Lozano and V. Bekeris, Phys. Rev. B 81, 184520 (2010).