Related papers: Pinning effects on hot-electron vortex flow instab…
We report on the anisotropy of the vortex motion surface impedance of a \fst thin film grown on a CaF$_2$ substrate. The dependence on the magnetic field intensity up to 1.2 T and direction, both parallel and perpendicular to the sample…
The dynamics of quantized magnetic vortices and their pinning by materials defects determine electromagnetic properties of superconductors, particularly their ability to carry non-dissipative currents. Despite recent advances in the…
We performed systematic AC susceptibility and magnetic moment measurements to investigate the vortex dynamics and pinning in the $EuRbFe_4As_4$ single crystal as a function of temperature, frequency, and DC magnetic field. The vortex…
We investigate the phenomenon of decay of a supercurrent in a superconducting thin film in the absence of an applied magnetic field. The resulting zero-temperature resistance derives from two equally possible mechanisms: 1) quantum…
Controlled engineering of vortex pinning sites in copper-oxide superconductors is a critical issue in manufacturing devices based on magnetic flux quanta. To address this, we employed a focused He-ion beam (He-FIB) to irradiate thin…
The magnetic field dependent critical current density $j_c(B)$ of a MgB$_2$ bulk sample has been obtained by means of magnetization hysteresis measurements. The $j_c(B)$ curves at different temperatures demonstrate a crossover from single…
We study thermal effects on pinning and creep in type-II superconductors where vortices interact with a low density $n_p$ of strong point-like defects with pinning energy $e_p$ and extension $\xi$, the vortex core size. Defects are…
The magnetic field dependence of the critical current is studied in single crystal samples of the weak pinning type-II superconductor 2H-NbSe$_2$ in the high temperature and the low field region of the (H,T) phase space, in the vicinity of…
We report the influence of intrinsic superconducting parameters on the vortex dynamics and the critical current densities of a MgB$_2$ thin film. The small magnetic penetration depth of \lambda = 50 nm at T=4 K is related to a clean…
We show that the superconducting transition temperature T_c(H) of a very thin highly disordered film with strong spin-orbital scattering can be increased by parallel magnetic field H. This effect is due to polarization of magnetic impurity…
In framework of Ginzburg-Landau model it is shown that narrow superconducting film with width w ~ 3-8 \xi(T) (\xi(T) is a temperature dependent coherence length) exhibits unusual transport properties. In the absence of bulk pinning its…
The presence of quantum vortices determines the electromagnetic response of superconducting materials and devices. Controlling the vortex motion, their pinning on intrinsic and artificial defects is therefore essential for superconducting…
We examine vortex pinning and dynamics in thin-film superconductors interacting with square and rectangular pinning arrays for varied vortex densities including densities significantly larger than the pinning density. For both square and…
Disorder can have remarkably disparate consequences in superconductors, driving superconductor-insulator transitions in ultrathin films by localizing electron pairs and boosting the supercurrent carrying capacity of thick films by…
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…
We report on the thickness dependence of the superconducting characteristics including critical current Ic, critical current density Jc, transition temperature Tc, irreversibility field Hirr, bulk pinning force plot Fp(H), and the normal…
The flux pinning mechanism of NdO0.82F0.18FeAs superconductor made under high pressure, with a critical temperature, Tc, of 51 K, has been investigated in detail in this work. The field dependence of the magnetization and the temperature…
We present the experimental observation of magnetic field line curvature at the surface of a superconducting film by local quantitative magneto-optics. In addition to the knowledge of the full induction field at the superconductor surface…
It is shown that the large effect of heavy ion-irradiation on the thermodynamical properties of the anisotropic superconductor YBa$_{2}$Cu$_{3}$O$_{7-\delta}$ extends well into the superconducting fluctuation regime. The presence of the…
The magnetic phase transition is experimentally known to give rise to an anomalous temperature-dependence of the electron resistivity in ferromagnetic crystals. Phenomenological theories based on the interaction between itinerant electron…