Effect of pinning and driving force on the metastability effects in weakly pinned superconductors and the determination of spinodal line pertaining to order-disorder transition

Abstract

We explore the effect of varying drive on metastability features exhibited by the vortex matter in single crystals of 2H-NbSe${}_2$ and CeRu${}_2$ with varying degree of random pinning. An optimal balance between the pinning and driving force is needed to view the metastability effects in typically weakly pinned specimen of low temperature superconductors. As one uses samples with larger pinning in order to differentiate the response of different metastable vortex states, one encounters a new phenomena, viz., the second magnetization peak (SMP) anomaly prior to the PE. Interplay between the path dependence in the critical current density and the non-linearity in the electromagnetic response determine the metastability effects seen in first and the third harmonic response of the ac susceptibility across the temperature regions of the SMP and the PE. The limiting temperature above which metastability effects cease can be conveniently located in the third harmonic data, and the observed behavior can be rationalized within the Beans Critical State model. A vortex phase diagram showing the different vortex phases for a typically weakly pinned specimen has been constructed via the ac susceptibility data in a crystal of 2H-NbSe${}_2$ which shows the SMP and the PE anomalies. The phase space of coexisting weaker and stronger pinned regions has been identified. It can be bifurcated into two parts, where the order and disorder dominate, respectively. The former part continuously connects to the reentrant disordered vortex phase pertaining to the small bundle pinning regime, where the vortices are far apart, interaction effects are weak and the polycrystalline form of flux line lattice prevails.

arXiv commentSubmitted to the Special Volume on Vortex State Studies, Pramana J. Phys

References in corpus (12)

• Elastic theory of flux lattices in presence of weak disorder
• Metastability and Glassy Behavior of a Driven Flux-Line Lattice
• Weak- to strong pinning crossover
• Anomalous Peak Effect in CeRu2 and NbSe2 : Fracturing of a Flux Line Lattice?
• STM Imaging of Flux Line Arrangements in the Peak Effect Regime
• Peak Effect, Fishtail Effect and Plateau Effect : The Reentrant Amorphization of Vortex Matter in 2H-NbSe_2
• Disordered Type-II Superconductors: A Universal Phase Diagram for Low-T${}_c$ Systems
• Melting of the vortex lattice in high $T_c$ superconductors
• A study of supercooling of the disordered vortex phase via minor hysteresis loops in 2H-NbSe_2
• Exploring metastability via the third harmonic measurements in single crystals of $2H$-$NbS{e}_2$ showing anomalous Peak effect
• Critical current and topology of the supercooled vortex state in NbSe2
• Domain regime in two-dimensional disordered vortex matter

Cited by in corpus (3)

• Evolution in the split-peak structure across the Peak Effect region in single crystals of $2H$-NbSe${}_2$
• Pulverization of the flux line lattice, the phase coexistence and the spinodal temperature of the order-disorder transition in a weakly pinned crystal of Yb${}_3$Rh${}_4$Sn${}_{13}$
• Critical points in the Bragg glass phase of a weakly pinned crystal of Ca${}_3$Rh${}_4$Sn${}_{13}$