High-temperature superconductivity

About: High-temperature superconductivity is a research topic. Over the lifetime, 7263 publications have been published within this topic receiving 175377 citations. The topic is also known as: high-temperature superconductivity.

Josephson effect in high-temperature superconductors and in structures based on them

Abstract: A review is made of the current status of investigations of the Josephson effect in hightemperature superconducting materials and in structures based on them. The results are given of experimental investigations of the influence of various factors on superconducting properties of surface layers of high-temperature materials, such as the conditions during synthesis and cleaning of their surface, and also data on the ohmic contacts. This information is used to analyze the experimental results obtained for Josephson junctions between high- and low-temperature superconductors and between two high-temperature superconductors. The following junctions are considered: point contacts, tunnel junctions, SNS structures with direct conduction, junctions at internal grain boundaries in high-temperature superconducting ceramics and films, and also junctions at microcracks in high-temperature superconducting crystals. These results are compared with the predictions of theoretical models of Josephson junctions developed on the basis of the BCS theory. It is concluded that the available data are insufficient not only to determine the validity of the BCS theory in the description of high-temperature superconductors, but also to provide a reliable qualitative identification of the physical structure of the junctions. Possible topics for further experimental investigations of the Josephson effect in high-temperature superconducting junctions with direct and tunnel conduction are suggested.

Interface induced high temperature superconductivity in single unit-cell FeSe on SrTiO3(110)

Abstract: We report high temperature superconductivity in one unit-cell (1-UC) FeSe films grown on SrTiO3 (STO)(110) substrate by molecular beam epitaxy. By in-situ scanning tunneling microscopy measurement, we observe a superconducting gap as large as 17 meV on the 1-UC FeSe films. Transport measurements on 1-UC FeSe/STO(110) capped with FeTe layers reveal superconductivity with an onset transition temperature (TC) of 31.6 K and an upper critical magnetic field of 30.2 T. We also find that TC can be further increased by external electric field although the effect is weaker than that on STO(001) substrate.

Crystal Structure and Superconductivity in Ba2Y1-xPrxCu3O7-y

Abstract: Crystal structures and superconductive properties of the solid solution Ba2Y1-xPrxCu3O7-y (0≤x≤1) are studied Although Ba2Y1-xPrxCu3O7-y has an orthorhombic structure which is isomorphic with Ba2YCu3O7-y, Tc decreases monotonically with increasing Pr concentration, and superconductivity disappears at around x=06 The Rietveld analysis of X-ray powder diffraction data shows that both Cu(1)-O(3) bond length and the structural asymmetry of the Cu(2)O2 planes increase by the substitution of Pr for Y Such structural changes induce the carrier density reduction and localization effects, which may cause the suppression of superconductivity in this system

Vortex pinning properties in Fe-chalcogenides

Abstract: Among the families of iron-based superconductors, the 11-family is one of the most attractive for high field applications at low temperatures. Optimization of the fabrication processes for bulk, crystalline and/or thin film samples is the first step in producing wires and/or tapes for practical high power conductors. Here we present the results of a comparative study of pinning properties in iron-chalcogenides, investigating the flux pinning mechanisms in optimized Fe(SeTe x ) and FeSe samples by current–voltage characterization, magneto-resistance and magnetization measurements. In particular, from Arrhenius plots in magnetic fields up to 9 T, the activation energy is derived as a function of the magnetic field, whereas the activation energy as a function of temperature, is derived from relaxation magnetization curves. The high pinning energies, high upper critical field versus temperature slopes near critical temperatures, and highly isotropic pinning properties make iron-chalcogenide superconductors a technological material which could be a real competitor to cuprate high temperature superconductors for high field applications.

Selected Topics in Superconductivity

Abstract: Structural aspects and Cu mixed valence in Bi- and TI-based cuprate superconductors (B. Raveau) superconductivity in cuprates and other oxides (H.R. Ott) organic superconductors (T. Ishiguro) superconducting granular films (S-I. Kobayashi) breaking the log-jam in many-body physics - fermi surfaces without fermi liquids (P.W. Anderson) Mott transition in the Hubbard model (B.S. Shastry) fundamentals of resonating valence bond (RVB) theory and its applications to high-Tc superconductivity (G. Baskaran) anyons and superconductivity (S. Das Sarma) superconducting pairing in layered superconductors (S.S. Jha) crystal field excitations in high-Tc superconducting materials (A. Furrer) superconductivity in high magnetic fields from a microscopic theory (A.K. Rajagopal) non-equilibrium superconductivity (R. Tidecks) NMR study in highly correlated systems - heavy fermion and high-Tc superconductors (K. Asayama) superconductivity and magnetism in heavy fermion compounds (F. Steglich) transport properties in the mixed state of high temperature superconductors (A. Freimuth) tunnelling spectroscopy of copper oxide superconductors (J. Akimitsu) pulsed laser and cylindrical magnetron sputter deposition of epitaxial metal oxide thin films (T. Venkatesan).