Depinning and dynamics of ac driven vortex lattices in random media

Daroca, D. Pérez; Lozano, Gustavo; Pasquini, G.; Bekeris, V.

doi:10.1103/physrevb.81.184520

Cited by 23 publications

(46 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…To realize random organization, initially a highly disordered vortex configuration was prepared for each measurement. This has been accomplished by driving the vortices with a small dc current yielding 100 μV, which corresponds to plastic flow, for a sufficiently long time to reach the steady state, and then the vortex configuration was frozen by abruptly switching off the dc current [27,38]. The thus-prepared highly disordered initial vortex assembly was periodically driven by square ac currents giving rise to displacement amplitudes in the range d=0.6-20 μm (i.e.…”

Section: Resultsmentioning

confidence: 99%

Memory formation and evolution of the vortex configuration associated with random organization

et al. 2017

View full text Add to dashboard Cite

We study the general phenomenon of random organization using a vortex system. When a periodic shear with a small shear amplitude d inp is applied to many-particle (vortex) assemblies with a random distribution, the particles (vortices) gradually self-organize to avoid future collisions and transform into an organized configuration. This is detected from the time-evolution of the voltage V t ( ) (average velocity) that increases towards a steady-state value. From the subsequent readout measurements of V t ( ) using various shear amplitudes, we find that the information of the input shear amplitude d inp is memorized in the configuration of the vortex distributions in the transient as well as the steady state, and that it is readable. We also find that the transient vortex configuration formed during random organization is not microscopically homogeneous but consists of disordered and organized regions.

show abstract

Section: Resultsmentioning

confidence: 99%

Memory formation and evolution of the vortex configuration associated with random organization

et al. 2017

View full text Add to dashboard Cite

show abstract

“…Although particular effort has been devoted to understand the dynamic behavior under dc drive, somewhat less attention has been paid to ac excitations [10][11][12][13][14][15][16]. Unfortunately, the extrapolation of the findings obtained under dc drive to predict the ac dynamics is not always straightforward.…”

Section: Introductionmentioning

confidence: 99%

Closer look at the low-frequency dynamics of vortex matter using scanning susceptibility microscopy

et al. 2014

View full text Add to dashboard Cite

Using scanning susceptibility microscopy, we shed light on the dynamics of individual superconducting vortices and examine the hypotheses of the phenomenological models traditionally used to explain the macroscopic ac electromagnetic properties of superconductors. The measurements, carried out on a 2H-NbSe 2 single crystal at relatively high temperature (T = 6.8 K), show a linear amplitude dependence of the global ac susceptibility for excitation amplitudes between 0.3 and 2.6 Oe. We observe that the low amplitude response, typically attributed to the oscillation of vortices in a potential well defined by a single, relaxing, Labusch constant, actually corresponds to strongly nonuniform vortex shaking. This is particularly pronounced in the field-cooled disordered phase, which undergoes a dynamic reorganization above 0.8 Oe as evidenced by the healing of lattice defects and a more uniform oscillation of vortices. These observations are corroborated by molecular dynamics simulations when choosing the microscopic input parameters from the experiments. The theoretical simulations allow us to reconstruct the vortex trajectories, providing deeper insight into the thermally induced hopping dynamics and the vortex lattice reordering.

show abstract

“…The dc depinning force per unit length F dc c = φ 0 J c ≈ 0.01f 0 was obtained by increasing a dc F L until the mean velocity v exceeds a "criterion voltage." The shaking frequencies have been selected in the low frequency regime (ω ω c ∼ α L η ∼ 0.11), 10 where pinning forces dominate over viscous drags, because the experimental shaking frequencies are well below f c = ω c /2π > 1 MHz Figure 3(b) shows the calculated mean velocity as a function of time during two shaking cycles for two different frequencies.…”

mentioning

confidence: 99%

Dynamics of superconducting vortices driven by oscillatory forces in the plastic-flow regime

et al. 2011

Self Cite

View full text Add to dashboard Cite

We study experimentally and theoretically, the reorganization of superconducting vortices driven by oscillatory forces near the plastic depinning transition. We show that the system can be taken to configurations that are tagged by the shaking parameters but keep no trace of the initial conditions. In experiments performed in NbSe 2 crystals, the periodic drive is induced by ac magnetic shaking fields and the overall order of the resulting configuration is determined by noninvasive 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.

show abstract

Depinning and dynamics of ac driven vortex lattices in random media

Cited by 23 publications

References 31 publications

Memory formation and evolution of the vortex configuration associated with random organization

Memory formation and evolution of the vortex configuration associated with random organization

Closer look at the low-frequency dynamics of vortex matter using scanning susceptibility microscopy

Dynamics of superconducting vortices driven by oscillatory forces in the plastic-flow regime

Contact Info

Product

Resources

About