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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…
A perpendicular magnetic field penetrating a thin type-II superconductor slab produces vortices, with one vortex per flux quantum, h/2e. The vortices interact repulsively and form an ordered array (Abrikosov lattice) in clean systems, while…
We report on the field dependence of the microwave complex resistivity data in YBa$_2$Cu$_3$O$_{7-x}$/BaZrO$_3$ films grown by PLD at various BaZrO$_3$ content. The data, analyzed within a recently developed general framework for the…
Recently, detailed real space imaging using scanning tunneling spectroscopy of the vortex lattice in a weakly pinned a-MoGe thin film revealed that the vortex lattice melts in two steps with temperature or magnetic field, going first from a…
Here we give a results of experimental study of enhancement of superconductivity by microwave irradiation in superconducting films. An influence of the power, frequency of microwave irradiation, as well as temperature and width of…
We measured the terahertz (THz) complex conductivity of Ca doped YBa_{2}Cu_{3}O_{7-\delta} thin films in the frequency range of 0.1 to 3 THz (3 to 100 cm^{-1}) and at a temperature range of 20 to 300 K. The films were measured using both…
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…
A cavity perturbation technique is used to study the microwave response of the organic superconductor k-(BEDT-TTF)2Cu(NCS)2. Observation of a Josephson plasma resonance, below Tc (approx. 10 K), enables investigation of the vortex structure…
We present a microwave characterization of a DyBa$_{2}$Cu$_{3}$O$_{7-x}$ single domain, grown by the top-seeded melt-textured technique. We report the (a,b) plane field-induced surface resistance, $\Delta R_s(H)$, at 48.3 GHz, measured by…
We use a near-field magnetic microwave microscope to investigate and compare rf vortex nucleation in two superconducting radio-frequency (SRF)-quality Nb3Sn films fabricated by different methods: a conventional vapor-diffused film and an…
We describe quantitative imaging of the sheet resistance of metallic thin films by monitoring frequency shift and quality factor in a resonant scanning near-field microwave microscope. This technique allows fast acquisition of images at…
The Josephson vortices dynamic in superconducting $YBa_2Cu_3O_x$ ceramics was studied in frequency range 0.01-0.5 Hz by ac susceptibility measurements in non complete magnetic flux penetration regime. We have found that with the increase of…
Precision measurements of the microwave surface resistance $R_{s}$ of in situ $MgB_{2}$ films directly reveal an exponential behavior of $R_{s}$ at low temperature indicating a fully-gapped order parameter. The entire temperature dependence…
The current-voltage characteristics of a porous superconductor Bi2Sr2Ca2Cu3Ox (Bi2223) have been measured at temperature range from 10 to 90 K. The experimental dependences have been analyzed within the model allowing for pinning by…
We have performed flux noise and AC-susceptibility measurements on two 400 nm thick MgB$_2$ films. Both measurement techniques give information about the vortex dynamics in the sample, and hence the superconducting transition, and can be…
The hot-electron vortex flow instability in superconducting films in magnetic field $B$ at substrate temperature $T_0 \ll T_c$ is theoretically considered in the presence of pinning. The magnetic field dependence of the instability critical…
The optical properties of Nd$_{0.7}$Sr$_{0.3}$MnO$_3$ thin films have been studied from 5 meV to 25 meV and from 0.25 eV to 3 eV, at temperatures from 15 K to 300 K and magnetic fields up to 8.9 T. A large transfer of spectral weight from…
We present measurements of the microwave complex conductivity at 23.9 and 48.2 GHz in YBa$_{2}$Cu$_{3}$O$_{7-\delta}$ films, in the fluctuational region above $T_{c}$. With increasing temperature, the fluctuational excess conductivity drops…
Continuously graded ferromagnetic thin films represent a new class of magnonic materials, where a spin-wave resonance spectrum can be tuned in resonance frequencies/fields, number of modes and even dispersion law by the magnetic properties…
We have carried out non-linear microwave (8 GHz) surface impedance measurements of three YBaCuO thin films in dc magnetic fields $H_{dc}$ (parallel to c axis) up to 12 mT using a coplanar resonator technique. In zero dc field the three…