Superconducting Transition Temperature (superconducting + transition_temperature)

Distribution by Scientific Domains


Selected Abstracts


Correlation between the residual resistivity ratio and the power-law of the normal-state resistivity in MgB2

CRYSTAL RESEARCH AND TECHNOLOGY, Issue 1 2008
I. M. Obaidat
Abstract MgB2 polycrystalline superconducting specimens were irradiated with several doses of ,-rays up to 100 MR. An increase in the normal state resistivity and a broadening of the resistive transition to the superconducting state were observed with increasing ,-irradiation dose. Although very small changes to the superconducting transition temperature were obtained after ,-irradiation, different temperature dependence of normal-state resistivity and different residual resistivity ratios, RRR were obtained for different doses. We have found a correlation between RRR and the power law dependence of resistivity, n as the irradiation dose increases. This correlation may be an indication that the electron-phonon interaction is important in these samples. These results are attributed to the disorder caused by ,-rays. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]


Developments and Perspectives of Iron-based High-Temperature Superconductors,

ADVANCED MATERIALS, Issue 19 2008
Hai-Hu Wen
Abstract Since the first report on superconductivity at 26,K in F-doped LaOFeAs at the end of February 2008, the superconducting transition temperature has been quickly raised to about 55,K and many new superconductors have been found, and superconductors with a higher condensing temperature are expected in this system. In this brief Research News article, the author will relate the enormous interest that has been generated towards new superconductor exploration, the refinement and tailoring of the single phase of the available superconductors, the growth of single crystals, and the theoretical and experimental efforts toward targeting the mechanism. Finally, a preliminary comparison between the iron-based system and the cuprates is given, as well as perspectives on these new iron-based superconductors. [source]


A Simple Sol,Gel Synthesis of Superconducting MgB2 Nanowires,

ADVANCED MATERIALS, Issue 14 2006
M. Nath
Superconducting MgB2 nanowires have been synthesized in a very high yield by a simple soft-chemical approach combining sol-gel chemistry and pyrolysis techniques (see main image in the figure; scale bar: 10,,m). The long thin nanowires show a superconducting transition temperature, Tc, of ca.,39,K, as shown in the magnetization curve in the inset of the figure. [source]


Homes relation in the attractive Hubbard model in d = ,

PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 1 2006
M. Bak
Abstract Lack of the recognized theory of high-temperature superconductivity (HTS) has led to an intense experimental and theoretical search for some universal relationships, which might unravel the physics behind the HTS. One of the most known is so called Uemura relation, ,s(0) , Tc, where ,s is superfluid density and Tc is the superconducting transition temperature. Recently Homes et al. [Nature 430, 539 (2004)] reported a new universal scaling relation, ,s , ,dc(Tc) · Tc, where ,dc(T ) is dc conductivity. In the present paper Homes relation is investigated theoretically in the limit of infinite dimensions in the second order perturbation theory. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]


Transport properties of hydrogen-doped (Zr803d20)1,xHx (3d = Co, Ni) metallic glasses

PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 4 2004
I. Kokanovi
Abstract The electrical resistivities of hydrogen-doped (Zr803d20)1,xHx (3d = Ni, Co; x , 0.11) metallic glasses have been measured at temperatures between 2 K and 110 K and in magnetic fields up to 1 T for various dopant concentrations. These systems have a high room-temperature resistivity (, > 160 ,, cm) and become superconducting below 4 K. The increase of the room-temperature resistivity and its temperature coefficient with hydrogen dopant concentration is explained as due to an increase of disorder with hydrogen-doping. The temperature and magnetic field dependence of the resistivity has been analysed using theoretical models of weak-localisation and electron,electron interaction in disordered conductors. The hydrogen dopant is found to reduce the effective electron diffusion constant, D, the spin-orbit scattering rate, ,,1so, the superconducting transition temperature, Tc, and broadens the superconducting transition region. The contribution of the Maki-Thompson interaction to the magnetoresistivity is also reduced. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]