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.

Superconducting properties of MgB2 bulk materials prepared by high-pressure sintering

Abstract: High-density bulk materials of a recently discovered 40 K intermetallic MgB2 superconductor were prepared by high-pressure sintering. Superconducting transition with the onset temperature of 39 K was confirmed by both magnetic and resistive measurements. Magnetization versus field (M–H) curve shows the behavior of a typical type-II superconductor and the lower critical field Hc1(0) estimated from the M–H curve is 0.032 T. The bulk sample shows good connection between grains and critical current density Jc estimated from the magnetization hysteresis using sample size was 5×104 A/cm2 at 20 K and 1 T. Upper critical field Hc2(0) determined by extrapolating the onset of resistive transition and assuming a dirty limit is 18 T.

Organic superconductors--new benchmarks.

Abstract: Recent advances in the design and synthesis of organic synthetic metals have yielded materials that have the highest superconducting transition temperatures ( T c ≈ 13 kelvin) reported for these systems These materials have crystal structures consisting of alternating layers of organic donor molecules and inorganic anions Organic superconductors have various electronic and magnetic properties and crystal structures that are similar to those of the inorganic copper oxide superconductors (which have high T c values); these similarities include highly anisotropic conductivities, critical fields, and short coherence lengths The largest number of organic superconductors, including those with the highest T c values, are charge-transfer salts derived from the electron donor molecule BEDT-TTF or ET [bis(ethylenedithio)-tetrathiafulvalene] The synthesis and crystal structures of these salts are discussed; their electrical, magnetic, and band electronic structure properties and their many similarities to the copper oxide superconductors are treated as well

Processing of bulk YBaCuO

Abstract: The author summarizes processing of bulk YBa2Cu3Ox superconductors with an emphasis placed on the relationship between microstructure and critical currents. Sintering is commonly used in ceramic processing but has been unsuccessful in producing high-Jc materials, primarily due to the weak links at grain boundaries. Melt processes have been found to be effective in increasing Jc values through a combination of grain alignment and the introduction of pinning centres. Some possible applications of melt processed superconductors in bulk form are also introduced in this review. Although many attempts have been made to fabricate long conductors, Jc values are still very small for long conductors, while the length is limited for high-Jc materials.

AC susceptibility of high temperature superconductors in a critical state model

Abstract: A critical state model for a granular superconductor is employed to calculate the temperature and AC and DC magnetic field dependence of the complex susceptibility, χ = χ ′ + iχ ″, of a sintered bulk YBa 2 Cu 3 O 7- δ superconductor. Inter granular Josephson vortices are assumed to sweep in and out of the weak-link network while intragranular Abrikosov vortices move in and out of the superconducting grains, both causing bulk pinning hysteresis losses. The predictions of the model for χ′ and χ″ are consistent with experimental data and model parameters which characterize a high temperature granular superconductor can be determined. These parameters are the inter- and intragranular pinning force densities, the fraction of the superconducting grains, the grain size distribution and a London penetration depth which neglects grain anisotropy.