Plasticity and Memory Effects in the Vortex Solid Phase of Twinned<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi>YBa</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow><mml:mrow><mml:msub><mml:mrow><mml:mi>Cu</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub></mml:mrow><mml:mrow><mml:msub><mml:mrow><mml:mi>O</mml:mi></mml:mrow><mml:mrow><mml:mn>7</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:ma

Valenzuela, Sergio O.; Bekeris, V.

doi:10.1103/physrevlett.84.4200

Cited by 59 publications

(79 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Furthermore, transport experiments in BSCCO have shown metastability in the zero-field-cooled state near the second peak as well as hysteretic V(I) curves [25], and magnetooptic imaging has revealed the coexistence of ordered and disordered phases [26]. Hysteretic and memory effects have also been observed near the second peak in YBCO [27][28][29].The presence of metastable states and superheating/supercooling effects strongly suggests that the orderdisorder transitions in these different materials are first order in nature. The many similarities also point to a universal behavior between the peak effect of low temperature superconductors and the peak effect and second peak effect of high temperature superconductors.…”

mentioning

confidence: 98%

Metastability and transient effects in vortex matter near a decoupling transition

et al. 2003

View full text Add to dashboard Cite

We examine metastable and transient effects both above and below the first-order decoupling line in a 3D simulation of magnetically interacting pancake vortices. We observe pronounced transient and history effects as well as supercooling and superheating between the 3D coupled, ordered and 2D decoupled, disordered phases. In the disordered supercooled state as a function of DC driving, reordering occurs through the formation of growing moving channels of the ordered phase. No channels form in the superheated region; instead the ordered state is homogeneously destroyed. When a sequence of current pulses is applied we observe memory effects. We find a ramp rate dependence of the V (I) curves on both sides of the decoupling transition. The critical current that we obtain depends on how the system is prepared.PACS numbers: 74.60Ge, 74.60JgVortices in superconductors represent an ideal system in which to study the effect of quenched disorder on elastic media. The competition between the flux-line interactions, which order the vortex lattice, and the defects in the sample, which disorder the vortex lattice, produce a remarkable variety of collective behavior [1]. One prominent example is the peak effect in low temperature superconductors, which appears near H c2 when a transition from an ordered to a strongly pinned disordered state occurs in the vortex lattice [2][3][4][5][6][7][8]. In high temperature superconductors, particularly BSCCO samples, a striking "second peak" phenomenon is observed in which a dramatic increase in the critical current occurs for increasing fields. It has been proposed that this is an order-disorder or 3D to 2D transition. [9][10][11][12][13] Recently there has been renewed interest in transient effects, which have been observed in voltage response versus time curves in low temperature superconductors [5][6][7][14][15][16][17]. In these experiments the voltage response increases or decays with time, depending on how the vortex lattice was prepared. The existence of transient states suggests that the disordered phase can be supercooled into the ordered region [21], producing an increasing voltage response, whereas the ordered phase may be superheated into the disordered region, giving a decaying response. In addition to transient effects, pronounced memory effects and hysteretic V(I) curves have been observed near the peak effect in low temperature materials [2,[4][5][6][7][16][17][18][19][20]. Memory effects are also seen in simulations [22]. Xiao et al. [7] have shown that transient behavior can lead to a strong dependence of the critical current on the current ramp rate. Recent neutron scattering experiments in conjunction with ac shaking have provided more direct evidence of supercooling and superheating near the peak effect [23]. Experiments on BSCCO have revealed that the high field disordered state can be supercooled to fields well below the second peak line [24]. Furthermore, transport experiments in BSCCO have shown metastability in the zero-field-cooled state near the second peak a...

show abstract

mentioning

confidence: 98%

Metastability and transient effects in vortex matter near a decoupling transition

et al. 2003

View full text Add to dashboard Cite

show abstract

“…For instance, Josephson plasma resonance experiments in Bi 2 Sr 2 CaCu 2 O 8 (BSCCO) suggest that the resonant field in FC samples is stationary while in ZFC samples it approaches the FC value asymptotically [10]. Still, thermomagnetic history effects in the solid vortex phase of pure twinned YBa 2 Cu 3 O 7 single crystals have been recently observed in ac susceptibility measurements [11]. On the numerical side, Olson et al studied how the fixed drive induced velocity (voltage response) depends upon time after different sample preparations, close to the order (3D) -disorder (2D) transition [12], focusing on the effect of superheating or supercooling the ordered and disordered phases [13].…”

mentioning

confidence: 99%

Slow relaxations and history dependence of the transport properties of layered superconductors

Exartier

Cugliandolo

2002

Phys. Rev. B

View full text Add to dashboard Cite

We study numerically the time evolution of the transport properties of layered superconductors after different preparations. We show that, in accordance with recent experiments in Bi2Sr2CaCu2O8 performed in the second peak region of the phase diagram (Portier el al., 2001), the relaxation strongly depends on the initial conditions and is extremely slow. We investigate the dependence on the pinning center density and the perturbation applied. We compare the measurements to recent findings in tapped granular matter and we interpret our results with a rather simple picture.The behavior of the flux-line array in type II superconductors is determined by two competing interactions, the vortex-vortex repulsion that favors order in the form of a hexagonal lattice, and the attraction between vortices and randomly placed pinning centers due to material defects that, as thermal fluctuations, favors disorder. This competition generates a very rich static phase diagram [1]. More recently, the evolution of the spatial ordering of vortices driven out of equilibrium by, e.g., an external current has been analyzed analytically [2], numerically [3] and experimentally [4].However, even in the absence of an external force, vortex systems show very rich nonequilibrium phenomena. Indeed, a hallmark of vortex dynamics is its history dependence. A vortex structure prepared by zero-field cooling (ZFC), in which the magnetic field is applied right after crossing the transition temperature, is expected to be more ordered than the one prepared by field cooling (FC), in which the magnetic field is applied before going through the transition [5-7] (see, however, [8]). Subsequently, thermal fluctuations allow for the rearrangement of the initial configurations. Studies of the evolution after FC and ZFC preparations of low-T c and high-T c type II superconductors have been performed with a variety of techniques that we non exhaustively summarize below.The initial current ramp in the IV characteristic of a FC 2H-NbSe 2 sample has a large hysteretic critical value, suggesting that vortices are strongly pinned [6,7]. Once the flux lines are depinned, and one applies a subsequent ramp, the critical current takes a smaller value. In ZFC samples the critical current in both ramps is small [6]. The presence of metastability and hysteresis depends on the speed of the current ramp imposed to the system [9]. The ac response and complex resistivity in 2H-NbSe 2 also show that the FC state is strongly pinned and disordered while the ZFC state is not [7] [12], focusing on the effect of superheating or supercooling the ordered and disordered phases [13].In this Letter we concentrate on a recent study of the long-time transport properties of BSCCO monocrystals after different preparations [14]. The experimental protocol is as follows. The same working conditions, given by a temperature T = 4.5K and a magnetic field, µ o H = 1.5T , perpendicular to the c-axis are initially attained via a FC or a ZFC procedure. These values fall in the second peak region [6]. ...

show abstract

“…The PE is found to be more pronounced in the weak pinning limit and progressively diminishes with increasing pinning strength [10,11]. An important characteristic of the PE phenomenon is the strong memory and history dependence of the various properties, and have been observed in static and dynamic experiments [12,13,14,15,16,17].…”

Section: Introductionmentioning

confidence: 99%

Peak Effect in Superconductors: Absence of Phase Transition and Possibility of Jamming in Vortex Matter

Chandran¹

2005

Int. J. Mod. Phys. B

View full text Add to dashboard Cite

The magnetic field B dependence of the critical current Ic for the vortex phase of a disordered superconductor is studied numerically at zero temperature. The Ic(B) increases rapidly near the upper critical field Bc2 similar to the peak effect (PE) phenomenon observed in many superconductors. The real space configuration across the PE changes continuously from a partially ordered domain (polycrystalline) state into an amorphous state. The topological defect density n d (B) ∼ e αB k with k > 1 for B ≥ 0.4Bc2. There is no evidence of a phase transition in the vicinity of the PE suggesting that an order-disorder transition is not essential for the occurrence of the PE phenomenon. An alternative view is presented wherein the vortex system with high dislocation density undergoes jamming at the onset of the PE.

show abstract

Plasticity and Memory Effects in the Vortex Solid Phase of TwinnedYBa2Cu3O7

Cited by 59 publications

References 29 publications

Metastability and transient effects in vortex matter near a decoupling transition

Metastability and transient effects in vortex matter near a decoupling transition

Slow relaxations and history dependence of the transport properties of layered superconductors

Peak Effect in Superconductors: Absence of Phase Transition and Possibility of Jamming in Vortex Matter

Contact Info

Product

Resources

About