Electronic properties of high temperature superconducting thin films grown by pulsed laser deposition

Chat with Graph Search

Ask any question about EPFL courses, lectures, exercises, research, news, etc. or try the example questions below.

DISCLAIMER: The Graph Chatbot is not programmed to provide explicit or categorical answers to your questions. Rather, it transforms your questions into API requests that are distributed across the various IT services officially administered by EPFL. Its purpose is solely to collect and recommend relevant references to content that you can explore to help you answer your questions.

We used a pump-probe technique to measure the transient change of optical reflectivity of both La2-xSrxCuO4, of various dopings, and slightly underdoped YBa2Cu3O7-x and NdBa2Cu3O7-x thin films. For the La2-xSrxCuO4 films, our data demonstrate the coexistence, in the superconducting state, of two coupled subsystems with different relaxation times and different contributions to the optical reflectivity. One subsystem is associated with the superconducting phase. By contrast. the data from YBa2Cu3O7-x, and NdB

The nonlinear behavior of High Temperature Superconductors (HTS) is often modeled by an E-J power law in order to describe their electromagnetic properties. This paper presents AC loss calculations in HTS tapes, performed by means of FEM commercial software using the A-V method. The implemented nonlinear model of the HTS tapes takes into account the B-dependence of the critical current density Jc and the power index n. The expressions for Jc(B) and n(B) are obtained from electrical measurements of a Bi-2223

We report on x-ray photoemission and absorption measurements on ruthocuprate and SrRuO3 samples. The ruthocuprates include samples that are both weak ferromagnets and superconductors for part of the phase diagram. The results indicate that adding hydrogen changes the many-body response on the CuO2 planes. The results further indicate that ferromagnetic order alters the core level states. We discuss implications of these data.

There is a need for chemically resistant coatings that protect the exposed surface of microfluidics components. Pinhole free films with low stress and a good uniformity on flat and inclined surfaces are required. In this study, amorphous silicon carbide (SiC) thin films have been deposited by RF magnetron sputtering on hat surfaces and into micromachined cavities of Si (100). The variation of RF power, deposition pressure and substrate bias voltage have been studied. Depending on the deposition conditions,

We report on the ab-plane polarized reflectance of an untwinned (Bi1.57Pb0.43)Sr2CaCu2O8+delta single crystal over the frequency range from 80 to 32 000 cm(-1) (10 meV-4 eV) at temperatures between 10 and 300 K. We find a clear anisotropy in the ab-plane optical conductivity above and below T-c, which is very similar to that formerly published data of Bi2Sr2CaCu2O8 (M.A. Quijada et al., Z. Phys. B 94, 255 (1994)). We employ both the one-component and two-component analyses to the optical data, which suggest

We investigate by means of high resolution angular resolved photoemission spectroscopy the classical one-dimensional organic conductor TTF-TCNQ and the inorganic one-dimensional conductor (TaSe4)(2)I. We measure dispersive features (1D bands) in accordance with band structure calculations. We observe typical bulk specific properties like the band periodicities (i.e. the Fermi wavevector) and the CDW-gap, which are in agreement with other experimental techniques. Peculiar for one-dimensional systems, we do n

The paper presents room temperature photoreflectance measurements carried out on the Au/ultrathin Si/n-crystalline GaAs structure with the silicon interlayer thickness gradually changing from about 4-27 Angstrom prepared in situ under ultra-high-vacuum conditions. A continuous change of the phase shift of the corresponding photoreflectance signal of more than 180 degrees has been observed in the Eg-critical-point oscillation of GaAs depending on the Si interlayer thickness. The explanation of the effect is

We report transport measurements on single crystals of Sr2RuO4-δ, grown by the flux technique. The temperature dependence of the Hall coefficient is similar to the one measured in cuprates, and the linear resistivity persists up to ~1000 K, while the superconductivity remains confined below 1 K. This suggests that the linear temperature dependence of resistivity is not an exclusive signature of the anomalous normal state of high-Tc cuprates but rather of layered oxides in general, especially single-layer pe

Photoluminescence intensity and emission wavelength of InAsP/InGaAsP and InGaAs/InGaAsP multi-quantum well (MQW) laser structures grown by chemical beam epitaxy (CBE) at 460 degrees C and V/III ratio of 2 are considerably affected by annealing at temperatures 600-650 degrees C which prevents lasing of these structures fused on GaAs substrates. It is shown that the degradation of luminescence characteristics can be decreased by increasing the growth temperature to 480 degrees C and V/III ratio to 4. InAsP/In

Dispersing 1D bands have been observed for the first time in an organic conductor by high resolution photoemission experiments on TTF-TCNQ (tetrathiafulvalene-tetracyanoquinodimethane). Their properties are extremely unusual: the bandwidth is much larger than traditional estimates, and the quasiparticle states are strongly renormalized, with no weight at the chemical potential. A deep pseudogap around the Fermi energy persists, and even increases, up to room temperature. We also report a direct determinatio

Lattice-matched ZnSe/InxGa1-xAs heterostructures were fabricated by molecular beam epitaxy on GaAs(001)2x4 surfaces. We find that the partial character of the strain relaxation within the ternary layer can be compensated by a suitable excess in the In concentration to match the free-surface lattice parameter to ZnSe. The surface of the II-VI epilayer, however, exhibits a cross-hatched pattern of surface corrugations oriented along orthogonal [110] directions. This complex surface morphology reflects the for

We measured typical quasi-one-dimensional organic metals (Bechgaard salts), using high resolution angle-resolved photoemission spectroscopy. We observe neither quasiparticle features near the chemical potential nor traces of a Fermi surface. The spectra, indicating a deep pseudogap around the Fermi energy, are incompatible with a Fermi liquid picture. None of the alternative interpretations we explored can fully explain the experimental data.

Electronic properties of high temperature superconducting thin films grown by pulsed laser deposition

Chat with Graph Search

Evidence for two coupled subsystems in the superconducting state of La2-xSrxCuO4

Finite element method simulation of ac loss in HTS tapes with B-dependent E-J power law

Photoabsorption and core-level photoemission study of ruthocuprates

Sputtered silicon carbide thin films as protective coating for MEMS applications

Optical study of an untwinned (Bi1.57Pb0.43)Sr2CaCu2O8+delta single crystal: ab-plane anisotropy

Photoemission study of organic and inorganic CDW-systems

X-ray photoemission and photoreflectance study of Au ultrathin Si/n-GaAs Schottky contacts and hydrogen plasma treated semi-insulating GaAs surfaces

On linear resistivity from ~1 to 103 K in Sr2RuO4-δ single crystals grown by flux technique

Thermal Stability of InP-Based Structures for Wafer Fused Laser Diodes

Band mapping and quasiparticle suppression in the one-dimensional organic conductor TTF-TCNQ

Strain and surface morphology in lattice-matched ZnSe/InxGa1-xAs heterostructures

Absence of quasiparticles in the photoemission spectra of quasi-one-dimensional Bechgaard salts