Related papers: Universal Lower Limit on Vortex Creep in Supercond…
Recently, the superconductors' community has witnessed an unsettled debate regarding whether iron-based superconductors, in particular FeSe and FeSe$_{1-x}$S$_x$, are in the Bardeen-Cooper-Shrieffer (BCS) - Bose-Einstein condensation (BEC)…
Current-voltage (I-V) characteristics of quench condensed, superconducting, ultrathin $Bi$ films in a magnetic field are reported. These I-V's show hysteresis for all films, grown both with and without thin $Ge$ underlayers. Films on Ge…
Flux line lattice in type II superconductors undergoes a transition into a "disordered" phase like vortex liquid or vortex glass, due to thermal fluctuations and random quenched disorder. We quantitatively describe the competition between…
We show results on the vortex core dissipation through current-voltage measurements under applied pressure and magnetic field in the superconducting phase of CeCoIn$_5$. We find that as soon as the system becomes superconducting, the vortex…
We investigated experimentally the frequency dependence of a superconducting vortex ratchet effect by means of electrical transport measurements and modeled it theoretically using the time dependent Ginzburg-Landau formalism. We demonstrate…
We present an extensive study of vortex dynamics in a high-quality single crystal of HgBa$_2$CuO$_{4+\delta}$ (Hg1201), a highly anisotropic superconductor that is a model system for studying the effects of anisotropy. From magnetization…
Vortices are topological defects associated with superfluids and superconductors, which, when mobile, dissipate energy destroying the dissipation-less nature of the superfluid. The nature of this "quantum dissipation" is rooted in the…
In type-II superconductors exposed to magnetic fields between upper and lower critical values, $H_{c1}$ and $H_{c2}$, penetrating magnetic flux forms a lattice of vortices whose motion can induce dissipation. Consequently, the magnetization…
The copper oxides present the highest superconducting temperature and properties at odds with other compounds, suggestive of a fundamentally different superconductivity. In particular, the Abrikosov vortices fail to exhibit localized states…
We use low-temperature scanning electron microscopy combined with SQUID detection of magnetic flux to image vortices and to investigate low-frequency flux noise in YBa$_2$Cu$_3$O$_7$ thin film SQUIDs. The low-frequency flux noise shows a…
In this thesis, we have studied the evolution of superconductivity in amorphous Molybdenum Germanium ($\textit{a}$-MoGe) thin films. The work can be broken down into two parts. In the first part, we investigate the effect of decreasing…
Similar to the optimal-doped, weak-ferromagnetic (WFM induced by canted antiferromagnetism, T$_{Curie}$ = 131 K) and superconducting (T$_{c}$ = 56 K) RuSr$_{2}$GdCu$_{2}$O$_{8}$, the underdoped RuSr$_{2}$EuCu$_{2}$O$_{8}$ (T$_{Curie}$ = 133…
We fabricate superconducting ion traps with niobium and niobium nitride and trap single 88Sr ions at cryogenic temperatures. The superconducting transition is verified and characterized by measuring the resistance and critical current using…
We describe high-Tc superconductivity in layered materials within a BCS theory as a BEC of massless-like Cooper pairons satisfying a linear dispersion relation, and propagating within quasi-2D layers of finite width defined by the charge…
Vortex breaking has been traditionally studied for nonuniform critical current densities, although it may also appear due to nonuniform pinning force distributions. In this article we study the case of a…
Superconductivity is inevitably suppressed in reduced dimensionality. Questions of how thin superconducting wires or films can be before they lose their superconducting properties have important technological ramifications and go to the…
In a liquid of superconducting vortices, a longitudinal thermal gradient generates a transverse electric field. This Nernst signal peaks at an intermediate temperature and magnetic field, presumably where the entropy difference between the…
We consider the problem of finite resistance $R$ in superconducting films with geometry of a strip of width $W$ near zero temperature. The resistance is generated by vortex configurations of the phase field. In the first type of process,…
In the recent experiment by Cren \textit{et al.} [Phys. Rev. Lett. \textbf{102}, 127005 (2009)], no hysteresis for vortex penetration and expulsion from the nano-island of Pb was observed. In the present paper, we argue that this effect can…
A profound change occurs in the stability of quantized vortices in externally applied flow of superfluid 3He-B at temperatures ~ 0.6 Tc, owing to the rapidly decreasing damping in vortex motion with decreasing temperature. At low damping an…