Volume 82, Number 4, May 2008
Article Number 47003
Number of page(s) 5
Section Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties
Published online 07 May 2008
EPL, 82 (2008) 47003
DOI: 10.1209/0295-5075/82/47003

Two-step depinning and re-entrant behavior of three-dimensional flux line lattices

Z. G. Zhao, Y. X. You, J. Wang and M. Liu

Department of Physics, Southeast University - Nanjing 210096, China

received 1 November 2007; accepted in final form 27 March 2008; published May 2008
published online 7 May 2008

We develop a three-dimensional flux line lattice (FLL) model with magnetic interactions between intraplane and interplane vortices to simulate the dynamic behavior of the flux flow in a disordered point-pinned system. A double-peak structure is found in the differential resistivity as a function of the driving current, corresponding to the two-step depinning behavior of the vortex motion. In between the two peaks there exists a new re-entrant pinning phase. The calculated results are summarized as a phase diagram of the interplane coupling strength of pancake vortices vs. the applied driving current. A huge peak effect and current-induced re-entrant pinning behavior appear in a narrow regime, where an unusual intrinsic pinning mechanism due to interlayer interactions dominates the peak effect. The phase diagram obtained is favorable for understanding the two-step depinning and re-entrant behavior observed recently experimentally.

74.25.Qt - Vortex lattices, flux pinning, flux creep.
74.25.Op - Mixed states, critical fields, and surface sheaths.
74.25.Dw - Superconductivity phase diagrams.

© EPLA 2008