2005/10/28 by Ajay D. Thakur, A. D. Thakur, S. S. Banerjee +3 · 1 citation
Materials Science · Physics and Astronomy · #Iron-based superconductors research #Magnetic and transport properties of perovskites and related materials #Physics of Superconductivity and Magnetism #cond-mat.stat-mech #cond-mat.supr-con
paper · pdf · doi:10.1007/bf02704945
published as Current trends in Vortex Physics, Pramana J. Physics, 66, 159 (2006) · Submitted to the Special Volume on Vortex State Studies, Pramana J. Phys
arxiv created 2005/10/28 · openalex publication_date 2006/01/01 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We explore the effect of varying drive on metastability features exhibited by the vortex matter in single crystals of 2H-NbSe2 and CeRu2 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-NbSe2 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.