Related papers: Effect of Carbon-Doping in Bulk Superconducting Mg…
We examine the superconducting anisotropy $\gamma_c = (m_c / m_{ab})^{1/2}$ of a metallic high-$T_c$ superconductor MgB$_2$ by measuring the magnetic torque of a single crystal. The anisotropy $\gamma_c$ does not depend sensitively on the…
We report the preparation of Mg1-xLixB2 compounds. Nearly single phased samples were obtained for x<0.3. The in-plane lattice parameter a decreases with Li doping, while the lattice parameter c does not show obvious change. The…
We have developed disk-shaped MgB2 bulk superconducting magnets (20, 30 mm in diameter, 10 mm in thickness) using the in-situ process from Mg and B powders and evaluated the temperature dependence of trapped magnetic field. A pair of two…
The electrical resistivity $\rho$ and upper critical field $H_{c2}$ were measured in MgB$_2$ disordered by nuclear reactor neutrons. We found that superconducting temperature $T_c$ decreases under irradiation from 40 to 5 K. Despite strong…
The effect of Li substitution for Mg and of Li-C co-substitution on the superconducting properties and crystal structure of MgB2 single crystals has been investigated. It has been found that hole doping with Li decreases the superconducting…
Chemical doping is a critical factor in the development of new superconductors or optimizing the superconducting transition temperature (Tc) of the parent superconducting materials. Herein, a new simple urea approach is developed to…
We report phase formation, and detailed study of magnetization and resistivity under magnetic field of MgB2 polycrystalline bulk samples prepared by Fe-tube encapsulated and vacuum (10-5 torr) annealed (750 0C) route. Zero-field-cooled…
BaFe2As2 is the parent compound of the '122' iron arsenide superconductors and crystallizes with the tetragonal ThCr2Si2 type structure, space group I4/mmm. A spin density wave transition at 140 K is accompanied by a symmetry reduction to…
This paper presents a brief review on the reported anisotropic properties of MgB2, in the superconducting state (e.g. upper critical field Hc2, field penetration depth, coherence length, energy gap) as well as in the normal state (e.g.,…
The hydrostatic pressure effect on the newly discovered superconductor MgB2 has been determined. The transition temperature Tc was found to decrease linearly at a large rate of -1.6 K/GPa, in good quantitative agreement with the ensuing…
By doping MgB_2 superconductor with SiC nano-particles, we have successfully introduced pinning sites directly into the crystal lattice of MgB_2 grains (intra-grain pinning). It became possible due to the combination of counter-balanced Si…
Based on the experimentally found existence of two gaps in MgB2 (one gap associated to the boron sigma-states and the other to the boron pi-states), the different contributions to the transport properties, electrical conductivity and Hall…
We report on the superconducting performance of the ex-situ SiC doped MgB2 monofilamentary tapes. Polycrystalline powders of MgB2 doped with 5 and 10 wt% SiC were synthesized by conventional solid-state reaction route and characterized for…
We report that the ternary MgB2-xCx compounds adopt an isostructural AlB2-type hexagonal structure in a relatively small range of nominal carbon concentration, x<0.1. The lattice parameter a decreases almost linearly with increasing carbon…
Porous magnesium diboride samples have been prepared by the heat treatment of a pressed mixture of Mg and MgB2 powders. It was found that linked superconducting structure is formed down to the minimum normalized density gamma= d/do= 0.16…
High-pressure superconductivity in a rare-earth doped Ca0.86Pr0.14Fe2As2 single crystalline sample has been studied up to 12 GPa and temperatures down to 11 K using designer diamond anvil cell under a quasi-hydrostatic pressure medium. The…
We have reported the effect of pressure on the magnetization, and transport properties in the nominal composition Pr$_{2}$Ba$_{4}$Cu$_{7}$O$_{15-\delta}$ synthesized by a sol-gel technique. A reduction treatment of the as-sintered sample in…
The superconductivity in Na0.3Co1-xMxO2.1.3H2O and the charge ordering in Na0.5Co1-xMxO2 have been investigated for M = Mn and Ti substituting for Co. We have first successfully synthesized the single-phase Na0.7Co1-xMxO2(M= Mn and Ti)…
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 size effect of the raw B powder on the MgB2 phase formation has been studied by the technique of in-situ high temperature resistivity (HT-rT) measurement. The onset temperature, Tonset, and the completion temperature, TPF, of the phase…