相关论文: Microstructure and Structural Defects in MgB2 Supe…
The proximity effect in normal/superconductor heterostructures is an intriguing phenomenon in that the normal side takes on the properties of a superconductor with an induced gap. However, the structural and pinning properties of vortices…
According to the crystal structure of MgB$_{2}$ and band structure calculations quasi-two-dimensional (2D) boron planes are responsible for the superconductivity. We report on critical fields and resistance measurements of 30 nm thick…
We studied the influence of sample preparation and defects in the superconducting properties samples using atomic ratios of Mg:B=1:1 and Mg:B=1:2. Samples were characterized by SEM, and XRD, and the magnetization properties were examined in…
We report on study of the electronic anisotropy of the newly discovered MgB2 superconductor using the in-plane resistivity measurements in magnetic field applied perpendicular and parallel to Mg and B planes of MgB2 single crystals. The…
The existence of two phases within one and the same hexagonal lattice of MgB2 compound, differing in Mg and B (in the homogeneity region) and especially in impurity oxygen content, as well as in microstructure, is demonstrated by various…
We report and analyze reversible magnetization measurements on a high quality MgB2 single crystal in the vicinity of the zero field transition temperature, T_c=38.83 K, at several magnetic fields up to 300 Oe, applied along the c-axis.…
In order to increase the accelerating gradient of Superconducting Radio Frequency (SRF) cavities, Magnesium Diboride (MgB2) opens up hope because of its high transition temperature and potential for low surface resistance in the high RF…
The MgB2 superconductor synthesized in a flowing argon atmosphere using nanometer magnesium powder as the raw materials, denoted as Nano-MgB2, has been studied by the technique of in-situ high temperature resistance measurement (HT-RT…
We investigate transport and magnetotransport properties of binary networks composed of superconducting (MgB2) and ferromagnetic (CrO2 or LSMO) nanoparticles. While for the LSMO/MgB2 system a single percolation threshold is observed, for…
A c-axis oriented thin film and a high density sintered pellet of MgB2 have been studied by x-ray photoemission spectroscopy, and compared to measurements from MgO and MgF2 single crystals. The as-grown surface has a layer which is Mg-rich…
We have performed a comparative study of two thin films of magnesium diboride (MgB2) grown by different techniques. The critical current density at different temperatures and magnetic fields was evaluated from magnetisation curves, the…
The study of the anisotropic superconductor MgB2 using a combination of scanning tunneling microscopy and spectroscopy reveals two distinct energy gaps at Delta1=2.3 meV and Delta2=7.1 meV. Different spectral weights of the partial…
Bulk samples of MgB2 have been formed by hot isostatic pressing (HIPping) of commercial powder at 100MPa and 950=B0C. The resulting material is 100% dense with a sharp superconducting transition at 37.5K. Microstructural studies have…
X-ray diffraction multipole refinements of single-crystalline Mg$_x$Al$_{1-x}$B$_2$ and polarization-dependent near-edge x-ray absorption fine structure at the B 1$s$ edge reveal a strongly anisotropic electronic structure. Comparing the…
The local composition Mg:B of MgB2 powder was systematically changed through annealing. Correlations were observed between the Mg loss and the lattice parameters a/c and the microstrain of MgB2. Direct wavelength-dispersive-spectrum and XRD…
Sintered powders and wires of superconducting $MgB_2$ have been fabricated under a variety of conditions in order to determine details of the diffusion of the $Mg$ into $B$ and to study the types of defects that arise during growth. For…
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…
We analyze the dislocation content of grain boundary (GB) phase junctions, i.e., line defects separating two different GB phases coexisting on the same GB plane. While regular GB disconnections have been characterized for a variety of…
Single crystals of MgB2 with a size up to 1.5x0.9x0.2 mm3 have been grown with a high pressure cubic anvil technique. The crystal growth process is very peculiar and involves an intermediate nitride, namely MgNB9. Single crystals of BN and…
This work studies the influence of microstructures and crystalline defects on the superconductivity of MgB2, with the objective to improve its flux pinning. A MgB2 sample pellet that was hot isostatic pressed (HIPed) was found to have…