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Related papers: Coherence lengths and anisotropy in MgB2 supercond…

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Transport and thermodynamic properties of a sintered pellet of the newly discovered $MgB_2$ superconductor have been measured to determine the characteristic critical magnetic fields and critical current densities. Both resistive transition…

Superconductivity · Physics 2009-11-07 D. K. Finnemore , J. E. Ostenson , S. L. Bud'ko , G. Lapertot , P. C. Canfield

The upper critical field Hc2 is evaluated for weakly-coupled two-band superconductors. By modeling the actual bands and the gap distribution of MgB2 by two Fermi surface spheroids with average parameters of the real material, we show that…

Superconductivity · Physics 2009-11-07 P. Miranovic , K. Machida , V. G. Kogan

Recent measurements of the magnetoresistance (MR) of amorphous superconducting thin films in tilted magnetic fields have displayed several surprising experimental details, in particular a strong dependence of the MR on field angle at low…

Superconductivity · Physics 2015-07-22 Elkana Porat , Yigal Meir

We investigated the magnetic field (H)-dependent optical conductivity spectra of MgB2 thin film in the far-infrared region. The H-dependences can be explained by the increase of normal metallic regions embedded in the superconducting…

Strongly Correlated Electrons · Physics 2009-11-07 H. J. Lee , J. H. Jung , K. W. Kim , M. W. Kim , T. W. Noh , Y. J. Wang , W. N. Kang , Eun-Mi Choi , Hyeong-Jin Kim , Sung-Ik Lee

In this paper we present the resistivity, the Seebeck effect, and the thermal conductivity measurements on a MgB2 sintered sample. Such transport properties highlight the role of the junctions between the grains to a different extent. In…

Superconductivity · Physics 2007-05-23 M. Putti , E. Galleani d'Agliano , D. Marre , F. Napoli , M. Tassisto , P. Manfrinetti , A. Palenzona

To identify the contributions of the multiband nature and the anisotropy of a microscopic electronic structure to a macroscopic vortex lattice morphology, we develop a method based on the Eilenberger theory near Hc2 combined with the…

Superconductivity · Physics 2014-04-22 Tomoya Hirano , Kenta Takamori , Masanori Ichioka , Kazushige Machida

High superconducting transition temperature is favorable for the applications of superconductors. Some cuprate superconductors have the transition temperatures above 100 K, such as the Hg- or Tl-based 1223 and 1234 phases, but many of them…

Superconductivity · Physics 2024-10-11 Meng-Jun Ou , Yuecong Liu , Yi Wang , Hai-Hu Wen

Electric and magnetic characterization of NbSe2 single crystals is first presented in detail. Then, some preliminary measurements of the fluctuation-diamagnetism (FD) above the transition temperature Tc are presented. The moderate uniaxial…

Superconductivity · Physics 2009-11-11 F. Soto , H. Berger , L. Cabo , C. Carballeira , J. Mosqueira , D. Pavuna , P. Toimil , F. Vidal

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…

Superconductivity · Physics 2009-11-07 N. Hakim , C. Kusko , S. Sridhar , A. Soukiassian , X. H. Zeng , X. X. Xi , .

We have found that single-crystal films can be grown on (0001) Al2O3 substrates through the golden relation of a perfect lattice-matching ratio between the a-axis lattice constants of MgB2 and Al2O3. Selected area electron diffraction…

Superconductivity · Physics 2011-08-10 Won Kyung Seong , Sangjun Oh , Won Nam Kang*

We report the results of angle dependent resistivity of NdFeAsO$_{0.82}$F$_{0.18}$ single crystals in the superconducting state. By doing the scaling of resistivity within the frame of the anisotropic Ginzburg-Landau theory, it is found…

Superconductivity · Physics 2009-11-13 Ying Jia , Peng Cheng , Lei Fang , Huan Yang , Cong Ren , Lei Shan , Chang-Zhi Gu , Hai-Hu Wen

Muon spin rotation (muSR) experiments were performed on the intercalated graphite CaC6 in the normal and superconducting state down to 20 mK. In addition, AC magnetization measurements were carried out resulting in an anisotropic upper…

Superconductivity · Physics 2011-08-29 F. Murányi , M. Bendele , R. Khasanov , Z. Guguchia , A. Shengelaya , C. Baines , H. Keller

In this article the Ginzburg-Landau theory ideas are considered in their application to the description of fluctuations influence on the superfluid density in superconductor. The conclusion about the availability of two incompatible…

Superconductivity · Physics 2009-10-20 Iogann Tolbatov

We have measured the low-temperature specific heat C(T) for polycrystalline MgB_2 prepared by high pressure synthesis. C(T) below 10 K vanishes exponentially, which unambiguously indicates a fully opened superconducting energy gap. However,…

Superconductivity · Physics 2009-11-07 H. D. Yang , J. -Y. Lin , H. H. Li , F. H. Hsu , C. J. Liu , S. -C. Li , R. -C. Yu , C. -Q. Jin

We performed far-infrared optical spectroscopy measurements on the heavy fermion compound URu 2 Si 2 as a function of temperature. The light's electric-field was applied along the a-axis or the c-axis of the tetragonal structure. We show…

Strongly Correlated Electrons · Physics 2011-11-17 J. Levallois , F. Lévy-Bertrand , M. K. Tran , D. Stricker , J. A. Mydosh , Y. -K. Huang , D. van der Marel

We present measurements of the superconducting coherence length \xi\ in thin (d < 100 \AA) films of MoGe alloy and Nb using a combination of linear and nonlinear mutual inductance techniques. As the alternating current in the drive coil is…

Sandwich-type MgB2 Josephson tunnel junctions (MgB2/AlOx/MgB2) have been fabricated using as-grown MgB2 films formed by molecular beam epitaxy. The junctions exhibited substantial supercurrent and a well-defined superconducting gap…

Superconductivity · Physics 2007-05-23 K. Ueda , S. Saito , K. Semba , T. Makimoto , M. Naito

Following earlier work on electron or hole liquids flowing through assemblies with magnetic fluctuations, we have recently exposed a marked correlation of the superconducting temperature Tc, for non s-wave pairing materials, with coherence…

Superconductivity · Physics 2007-05-23 G. G. N. Angilella , N. H. March , R. Pucci

We report measurements of the transport and the magnetic properties of high-quality, sub-millimeter-sized MgB2 single crystals with clear hexagonal-plate shapes. The low-field magnetization and the magnetic hysteresis curves show the vortex…

We have studied the optical properties of the heavy-fermion compound UNi2Al3 at frequencies between 100 GHz and 1 THz (3 cm^-1 and 35 cm^-1), temperatures between 2 K and 300 K, and magnetic fields up to 7 T. From the measured transmission…

Strongly Correlated Electrons · Physics 2012-11-14 Julia P. Ostertag , Marc Scheffler , Martin Dressel , Martin Jourdan