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Point contacts (PC) Andreev reflection dV/dI spectra for the antiferromagnetic (T_N =6K) superconductor (Tc=11K) ErNi2B2C have been measured for the two main crystallographic directions. Observed retention of the Andreev reflection minima…

Single atom junctions between superconducting niobium leads are produced using the Mechanically Controllable Break Junction technique. The current-voltage characteristics of these junctions are analysed using an exact formulation for a…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 B. Ludoph , N. van der Post , E. N. Bratus' , E. V. Bezuglyi , V. S. Shumeiko , G. Wendin , J. M. van Ruitenbeek

Tunneling spectroscopy of a Nb coupled carbon nanotube quantum dot reveals the formation of pairs of Andreev bound states (ABS) within the superconducting gap. A weak replica of the lower ABS is found, which is generated by quasi-particle…

Mesoscale and Nanoscale Physics · Physics 2014-02-27 A. Kumar , M. Gaim , D. Steininger , A. Levy Yeyati , A. Martin-Rodero , A. K. Huettel , C. Strunk

The Andreev reflection of narrow ferromagnet/superconductor point contacts is theoretically studied. We show that the conductance quantization depends on whether the contact region is superconducting or ferromagnetic as well as on the…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 Keiichirou Kikuchi , Hiroshi Imamura , Saburo Takahashi , Sadamichi Maekawa

The low-temperature conductance (G) characteristics between a normal metal and a clean superconductor (S) carrying a supercurrent $I_s$ parallel to the interface is theoretically investigated. Increasing $I_s$ causes lowering and broadening…

Superconductivity · Physics 2009-11-10 Degang Zhang , C. S. Ting , C. -R. Hu

We solve the coupled gap equations for the $\sigma$- and $\pi$-bands of MgB$_2$ in the vortex state and calculate the resulting field dependencies of the specific heat coefficient $\gamma$ and the thermal conductivity $\kappa $. The crucial…

Superconductivity · Physics 2009-11-10 L. Tewordt , D. Fay

We report synthesis, structure/micro-structure, resistivity under magnetic field [R(T)H], Raman spectra, thermoelectric power S(T), thermal conductivity K(T), and magnetization of ambient pressure argon annealed polycrystalline bulk samples…

Superconductivity · Physics 2015-05-13 V. P. S. Awana , Arpita Vajpaye , Monika Mudgel , H. Kishan , V. Ganesan , A. M. Awasthi , G. L. Bhalla

The magnetic penetration depth, $\lambda^{-2}(T)$, in the basal plane of a magnesium diboride (MgB$_2$) film was measured using a two-coil mutual inductance technique at 50 kHz. This film has $T_c\simeq 38$ K, $\Delta T_c \leq 1$ K, and…

The bulk upper critical field H_{c2}(T) of superconducting MgB_2 and its anisotropy are established by analyzing experimental data on the temperature and magnetic field dependences of the ab-plane thermal conductivity of a…

Superconductivity · Physics 2009-11-07 A. V. Sologubenko , J. Jun , S. M. Kazakov , J. Karpinski , H. R. Ott

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…

The prediction of material-specific properties of superconducting systems such as the electronic structure and the transition temperature is one of the major challenge in modern solid-state physics. In this paper we present the first…

Superconductivity · Physics 2016-09-21 Gabor Csire , Jozsef Cserti , Istvan Tutto , Balazs Ujfalussy

Thermal conductivity, point contact spectroscopy, angle-resolved photoemission and Raman spectroscopy measurements were performed on BaFe1.9Pt0.1As2 single crystals obtained from the same synthesis batch in order to investigate the…

This paper presents a study of the thermal transport properties of MgB$_2$ tapes differing in architecture, stabilization and constituent materials. The temperature and field dependence of thermal conductivity, $\kappa(T,B)$, was…

Superconductivity · Physics 2015-10-28 Marco Bonura , Carmine Senatore

Using intrinsic multiple Andreev reflections effect (IMARE) spectroscopy, we studied SnS contacts in the layered oxypnictide superconductors Sm$_{1-x}$Th$_x$OFeAs with various thorium doping and critical temperatures $T_C = 21-54$ K. We…

Superconductivity · Physics 2017-03-14 T. E. Kuzmicheva , S. A. Kuzmichev , K. S. Pervakov , V. M. Pudalov , N. D. Zhigadlo

Direct detection of superconductivity has long been a key strength of point-contact Andreev reflection. However, its applicability to atomic-scale imaging is limited by the mechanical contact of the Andreev probe. To this end, we present a…

Superconductivity · Physics 2024-04-23 Wonhee Ko , Jose L. Lado , Petro Maksymovych

We have measured the near-normal reflectance of Tl2Ba2CaCu2O8 (Tl2212) for energies from 0.1 to 4.0 eV at room temperature and used a Kramers-Kronig analysis to find the complex, frequency dependent dielectric function, from which the…

Andreev reflection-where an electron in a normal metal backscatters off a superconductor into a hole-forms the basis of low energy transport through superconducting junctions. Andreev reflection in confined regions gives rise to discrete…

We present new results of point-contact Andreev-reflection (PCAR) spectroscopy in single-phase Mg_{1-x}Al_{x}B_{2} single crystals with x up to 0.32. Fitting the conductance curves of our point contacts with the two-band…

Point contact Andreev reflection spectra have been taken as a function of temperature and magnetic field on the polycrystalline form of the newly discovered iron-based superconductor Sr2ScFePO3. A zero bias conductance peak which disappears…

Current-voltage characteristics and dynamic conductance of the superconductor - constriction - superconductor junctions in GdO(F)FeAs polycrystalline samples with critical temperatures Tc^local = 46 - 53 K were investigated. Two…