The optical properties of the heavy-fermion superconductor UNi2Al3 have been investigated at temperatures between 10 and 300 K using reflectance spectroscopy. A characteristic energy scale (vc590 cm ), with almost the same value as the coherence temperature T05100 K derived from measurements of the dc resistivity and susceptibility, is obtained from the optical conductivity. At high temperature...

in a systematic approach, we have investigated the effect of the presence of pb and sb in the bi site in a bscco (2223 phase) superconductor. there are some contradictory reports in substitution of sb in the bi site. some researchers report an increase in the tc of these materials. so, we have made an accurate stoichiometry of these superconductors and selected extra pure starting materials wit...

superconducting materials are capable of trapping extremely high magnetic fields. this property and meissner effect of superconductors causes a levitation force between bulk superconductors and a permanent magnet (pm). this levitation force has possible industrial applications such as permanent magnet guideways (pmg). because of the high price of permanent magnets, the optimization of pmg desig...

Topological superconductors have become a subject of intense research due to their potential use for technical applications in device fabrication and quantum information. Besides fully gapped superconductors, unconventional superconductors with point or line nodes in their order parameter can also exhibit nontrivial topological characteristics. This article reviews recent progress in the theore...

The possible existence of a sign-changing gap symmetry in BaFe2As2-derived superconductors (SC) has been an exciting topic of research in the last few years. To further investigate this subject we combine Electron Spin Resonance (ESR) and pressure-dependent transport measurements to investigate magnetic pair-breaking effects on BaFe1.9M0.1As2 (M = Mn, Co, Cu, and Ni) single crystals. An ESR sig...

We have performed low-temperature specific heat and thermal conductivity measurements of the Ni-based superconductor BaNi2As2 (T{c}=0.7 K) in a magnetic field. In a zero field, thermal conductivity shows T-linear behavior in the normal state and exhibits a BCS-like exponential decrease below T{c}. The field dependence of the residual thermal conductivity extrapolated to zero temperature is indi...

E. van Heumen,1 R. Lortz,1 A. B. Kuzmenko,1 F. Carbone,1 D. van der Marel,1 X. Zhao,2 G. Yu,2 Y. Cho,2 N. Barisic,2 M. Greven,2 C. C. Homes,3 and S. V. Dordevic3,* 1University of Geneva, 24, Quai E.-Ansermet, Geneva 4, Switzerland 2Department of Physics, Applied Physics, and Stanford Synchrotron Radiation Laboratory, Stanford University, Stanford, California 94305, USA 3Condensed Matter Physics...

The recently discovered superconductor Cu(x)Bi2Se3 is a candidate for three-dimensional time-reversal-invariant topological superconductors, which are predicted to have robust surface Andreev bound states hosting massless Majorana fermions. In this work, we analytically and numerically find the linearly dispersing Majorana fermions at k=0, which smoothly evolve into a new branch of gapless surf...

We report extensive measurements of quantum oscillations in the normal state of the Fe-based superconductor LaFePO, (T(c) approximately 6 K) using low temperature torque magnetometry and transport in high static magnetic fields (45 T). We find that the Fermi surface is in broad agreement with the band-structure calculations with the quasiparticle mass enhanced by a factor approximately 2. The q...