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Related papers: Scanning Tunneling Spectroscopy in MgB2

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The specific heat of two polycrystalline samples of MgB_2 is presented and analyzed (2 - 300 K, 0 - 16 T), together with magnetic properties. The main characteristics are a low density of states at the Fermi level, high phonon frequencies,…

Superconductivity · Physics 2007-05-23 Alain Junod , Yuxing Wang , Frederic Bouquet , Pierre Toulemonde

Using scanning tunneling spectroscopy at T = 4.2 K, we perform simultaneously the topographic imaging and the quasiparticle density of states (DOS) mapping in granular MgB2. We observe a new type of spectrum, showing a pronounced double…

Superconductivity · Physics 2009-11-07 F. Giubileo , D. Roditchev , W. Sacks , R. Lamy , J. Klein

Point-contact spectroscopy measurements on magnesium diboride reveal the existence of two superconducting energy gaps closing at the same transition temperature in line with the multiband model of superconductivity. The sizes of the two…

Superconductivity · Physics 2009-11-07 P. Samuely , P. Szabo , J. Kacmarcik , T. Klein , A. G. M. Jansen

Superconducting order parameter and its symmetry are important parameters towards deciphering the pairing mechanism in newly discovered superconducting systems. We report a study on penetration depth measurement on Nb2PdS5 that has recently…

Superconductivity · Physics 2016-04-20 Shruti , R. Goyal , V. P. S Awana , S. Patnaik

We report on the results of scanning tunneling spectroscopy measurements on single crystals of Mg2. Tunneling was performed both parallel and perpendicular to the crystalline c-axis. In the first case, a single superconducting gap (Delta_pi…

Superconductivity · Physics 2007-05-23 M. R. Eskildsen , M. Kugler , G. Levy , S. Tanaka , J. Jun , S. M. Kazakov , J. Karpinski , O. Fischer

Considerable excitement has been caused recently by the discovery that the binary boride system with stoichiometry MgB2 is superconducting at the remarkably high temperature of 39 K (1). This potentially opens the way to even higher Tc…

Measurements of the superconducting transition temperature Tc have been performed by the inductive method on MgB2 at pressures up to 28 GPa. Tc decreases with applied pressure, exhibiting a cusp at about 9 GPa. We interpret the appearance…

Superconductivity · Physics 2009-11-07 V. G. Tissen , M. V. Nefedova , N. N. Kolesnikov , M. P. Kulakov

We have studied the structure of the superconducting gap in MgB2 thin films by means of point-contact spectroscopy using a gold tip. The films were produced by depositing pure boron on a sapphire substrate, using e-beam evaporation,…

Within the BCS theory of superconductivity we calculate the superconducting gap at zero temperature for metallic hydrogen-graphene system in order to estimate the superconducting critical temperature of quasi two dimensional highly oriented…

Superconductivity · Physics 2009-02-11 N. García , P. Esquinazi

We have successfully prepared the MgB2 superconducting bulk and powdered materials by the method of combustion synthesis. The starting materials used in this study were powders of Mg and B. X-ray powder diffraction pattern was well assigned…

Superconductivity · Physics 2016-08-31 Yoshihiko Takano , Nobutaka Oguro , Yoshinari Kaieda , Kazumasa Togano

The review considers bulk MgB2-based materials in terms of their structure, superconducting and mechanical properties. Superconducting transition temperatures of 34.5-39.4 K, critical current densities of 1.8-1.0 x E6 A/sq.cm in self field…

Superconductivity · Physics 2009-12-25 T. A. Prikhna

We have constructed MgB2/Pb planar junctions for both temperature and field dependence studies. Our results show that the small gap is a true bulk property of MgB2 superconductor, not due to surface effects. The temperature dependence of…

Superconductivity · Physics 2009-11-07 Mohamed H. Badr , Mario Freamat , Yuri Sushko , K. -W. Ng

We report the temperature dependent magnetic penetration depth $\lambda(T)$ and the superconducting critical field $H_{c2}(T)$ in a 500-nm MgB$_{2}$ film. Our analysis of the experimental results takes into account the two gap nature of the…

We describe the development and performance of an ultra-high vacuum scanning tunneling microscope working under combined extreme conditions of ultra-low temperatures and high magnetic fields. We combined a top-loading dilution refrigerator…

Instrumentation and Detectors · Physics 2018-10-17 T. Machida , Y. Kohsaka , T. Hanaguri

We present electrical transport, magnetization, and specific heat measurements on bulk MgB2 samples (T_{c} = 38.5 K) synthesized under 200 MPa pressure using a process based on hot isostatic pressing with cooling under pressure. The samples…

Superconductivity · Physics 2009-11-07 N. A. Frederick , Shi Li , M. B. Maple , V. F. Nesterenko , S. S. Indrakanti

Composites consisting of MgB2 and Al, 11% by volume, undergo a transition to superconductivity onset at TC = 38 K, close to the value reported for pure MgB2. The transition appears to have broadened, as determined by both magnetic and…

Superconductivity · Physics 2009-11-07 A. Sharoni , O. Millo , G. Leitus , S. Reich

We develop the multi-band BCS model of superconductivity in the ultrathin films using the orthogonal tight-binding approximation for constructing the electron wavefunctions. This allows for relatively simple determination of the band…

Superconductivity · Physics 2014-07-15 Karol Szałowski

Magnetization studies have been carried out on superconducting MgB$_2$ (T$_c$=37K) in the temperature range of 2-50K and in magnetic field up to 5 Tesla. From these measurements, values of the lower critical field H$_c1$(0), upper critical…

Superconductivity · Physics 2007-05-23 Amish G. Joshi , C. G. S. Pillai , P. Raj , S. K. Malik

We present the main features of a home-built scanning tunneling microscope that has been attached to the mixing chamber of a dilution refrigerator. It allows scanning tunneling microscopy and spectroscopy measurements down to the base…

Superconductivity · Physics 2015-05-18 M. Marz , G. Goll , H. v. Loehneysen

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