Related papers: Pinning effects on hot-electron vortex flow instab…
The interplay between disorder and vortex--vortex interactions in strongly disordered superconductors in a magnetic field can stabilize a vortex-glass state, characterized by strong pinning and the absence of positional order. Yet its role…
The temperature and field dependence of the superfluid density $\rho_s$ in the vortex state of a d-wave superconductor are calculated using a microscopic model in the quasiclassical approximation. We show that at temperatures below T^{*}…
The magnetoresistivity and critical current density of well characterized Si-nanoparticle doped and undoped Cu-sheathed MgB$_{2}$ tapes have been measured at temperatures $T\geq 28$ K in magnetic fields $B\leq 0.9$ T. The irreversibility…
The ratchet effect is demonstrated theoretically for the simple model of a vortex in a thin superconducting film interacting with a periodic array of magnetic dipoles placed in the vicinity of the film . The pinning potential for the vortex…
It is shown that the temperature of the resistive transition $T_r$ of a superconducting film can be increased by a thin superconducting or normal overlayer. For instance, deposition of a highly conductive thin overlayer onto a dirty…
The effect of the Hall force on the pinning of vortices in type II superconductors is considered. A field theoretic formulation of the pinning problem allows a non-perturbative treatment of the influence of quenched disorder. A…
The resistive properties of thin amorphous NbO_{x} films with weak pinning were investigated experimentally above and below the second critical field H_{c2}. As opposed to bulk type II superconductors with weak pinning where a sharp change…
The temperature dependence of the nonlinear current-voltage ($I$-$V$) characteristics in highly underdoped La$_{2-x}$Sr$_{x}$CuO$_{4}$ ($x=0.07$ and 0.08) thick films has been studied in both zero and perpendicular magnetic fields $H$.…
Vortices in superconductors can help identify emergent phenomena but certain fundamental aspects of vortices, such as their entropy, remain poorly understood. Here, we study the vortex entropy in underdoped Bi$_2$Sr$_2$CaCu$_2$O$_{8+x}$ by…
We discuss the onset of irreversibility and entanglement of vortex lines in high Tc superconductors due to point disorder and thermal fluctuations using a simplified cage model. A combination of Flory arguments, known results from directed…
Superconducting thin films and layered crystals display a Nernst signal generated by short-lived Cooper pairs above their critical temperature. Several experimental studies have broadly verified the standard theory invoking Gaussian…
Novel behavior of the critical current density $j_{c}$ of a regularly perforated superconducting film is found, as a function of applied magnetic field $H$. Previously pronounced peaks of $j_{c}$ at matching fields were always found to…
The transverse (Hall) voltage in thin films of the high-temperature superconductor YBa$_{2}$Cu$_{3}$O$_{7-\delta}$ with an artificial periodic pinning array is investigated. Columnar defect regions along the crystallographic $c$ axis, in…
We study the phase diagram of flux lines in superconductors with columnar pins. Based on numerical exact diagonalisation simulations on small clusters, we get two phases of vortices: A low temperature pinned glass with diverging tilt…
We investigated the temperature dependence of the conductance fluctuations in thin films of the quasi-two-dimensional 1T-TaS$_2$ van der Waals material. The conductance fluctuations, determined from the derivative current-voltage…
Single crystal of Lu$_2$Fe$_3$Si$_5$ was studied with the tunnel-diode resonator technique in Meissner and mixed states. Temperature dependence of the superfluid density provides strong evidence for the two-gap superconductivity with almost…
The confinement of a superconductor in a thin film changes its Fermi-level density of states and is expected to change its critical temperature $T_c$. Previous calculations have reported large discontinuities of $T_c$ when the chemical…
We present measurements of the electrical resistivity, $\rho$, in epitaxial Cr films of different thicknesses grown on MgO (100) substrates, as a function of temperature, $T$. The $\rho(T)$ curves display hysteretic behavior in certain…
The diversity of vortex melting and solid-solid transition lines measured in different high-T$_{c}$ superconductors is explained, postulating a unified order-disorder phase transition driven by both thermally- and disorder-induced…
We have studied the vortex dynamics in the PrFeAsO$_{0.60}$F$_{0.12}$ superconducting sample by dc magnetization and dynamic magnetization-relaxation rate $(Q)$ measurements. The field dependence of the superconducting irreversible…