Related papers: Carbon substitution effect in MgB$_2$
Superconductivity was found for a rhenium boride Re3B at Tc=4.7 K and for ReB2 with Tc in the range from 4.5 to 6.3 K depending on the boron concentrations. Both compounds have the structure different from that of the simple layered…
Neutron powder diffraction has been used to characterize a sample of C-substituted MgB2 synthesized from Mg and B4C (with isotopically enriched 11B). The sample is multiphase, with the major phase [73.4(1) wt.%] being Mg(B1-xCx)2 with…
We employ ab initio modeling to investigate the possibility of attaining high-temperature conventional superconductivity in ambient-pressure materials based on the known MgB$_2$C$_2$ and recently proposed thermodynamically stable NaBC…
The normal state and superconducting properties of MgB2 and Mg1-xAlxB2 are discussed based on structural, transport, and high pressure experiments. The positive Seebeck coefficient and its linear temperature dependence for Tc<T<160 K…
We performed point-contact spectroscopy on the binary superconductor MgB$_2$. The differential conductance shows gap-related structures which vary in width and position from contact to contact. The distribution of energy gaps shows a…
The influence of lattice strain and Mg vacancies on the superconducting properties of MgB2 samples has been investigated. High quality samples with sharp superconducting transitions were synthesized. The variation in lattice strain and Mg…
Magnesium diboride has been thermally treated in the presence of Rb, Cs, and Ba. Magnetic susceptibility shows onsets of superconductivity in the resulting samples at 52K (Rb), 58K (Cs) and 45K (Ba). Room-temperature 11B NMR indicates to…
The effects of high-temperature vacuum-annealing induced Mg deficiency in MgB2 single crystals grown under high pressure were investigated. As the annealing temperature was increased from 800 to 975 C, the average Mg content in the MgB2…
We present a study of the superconducting transition in MgB2 using the ab-initio pseudopotential density functional method and the fully anisotropic Eliashberg equation. Our study shows that the anisotropic Eliashberg equation, constructed…
The influence of the nature of the boron precursor on the superconducting properties of polycrystalline MgB2 was studied. Critical current densities for the MgB2 made from high purity amorphous boron are at least a factor of three higher…
We present a study on the power dependence of the microwave surface impedance in thin films of the novel superconductor MgB2. 500 nm thick samples exhibiting critical temperatures ranging between 26 and 38 K are synthesized by an ex-situ…
We report specific heat measurements in neutron irradiated MgB2 samples, for which the critical temperature has been suppressed down to 8.5 K, but the superconducting transition remains extremely sharp, indicative of a defect structure…
We have synthesized MgB2/Pb planar junctions to study the temperature and field dependence of the superconducting energy gap of MgB2. The major peak occurs at Delta of about 2 meV, and this corresponds to a 2Delta/kBTc value of 1.18. While…
In this paper we introduce a novel method for fabricating MgB$_2$/MgO multilayers and demonstrate the potential for using them as a new model for disordered superconductors. In this approach we control the annealing of the MgB$_2$ to yield…
Point-contact measurements on the carbon-substituted Mg(B$_{1-x}$C$_x$)$_2$ filament/powder samples directly reveal a retention of the two superconducting energy gaps in the whole doping range from $x = 0$ to $x \approx 0.1$. The large gap…
Nanocrystalline MgB$_2$ produced by mechanical alloying has been shown to exhibit enhanced superconducting properties such as increased pinning and higher critical currents. However, the effects of the synthesis process on the intrinsic…
The recent discovery of superconductivity up to 32 K in the pressurized MoB2 reignites the interests in exploring high-Tc superconductors in transition-metal diborides. Inspired by that work, we turn our attention to the 5d transition-metal…
The evolution of the superconducting properties of the carbon-doped MgB2 superconductors, MgB(2-x)Cx (x= 0.02, 0.04, 0.06) have been investigated by the transverse-field muon spin rotation (TF-muSR) technique. The low-temperature…
We have performed high-resolution photoemission spectroscopy on MgB2 and observed opening of a superconducting gap with a narrow coherent peak. We found that the superconducting gap is s-like with the gap value of 4.5 meV at 15 K. The…
The effect of doping MgB2 with carbon nanotubes on transition temperature, lattice parameters, critical current density and flux pinning was studied for MgB2-xCx with x = 0, 0.05, 0.1, 0.2 and 0.3. The carbon substitution for B was found to…