Carbon doping has proven to be a highly effective strategy for enhancing the electrical properties of MgB2 wires, especially under a high magnetic field. However, unreacted doping material can persist as impurities due to uneven mixing or incomplete reactions, thereby detrimentally affecting electrical properties and their uniformity. In this study, we explore the application of pyrene doping to 18-multifilamentary MgB2 wires with a total length of 2.5 kilometers. The aim of this study is to minimize residues and maximize high-field critical current properties. Our investigation includes X-ray diffraction refinement, scanning electron microscopy observations, and a comprehensive characterization of critical current properties. We are presently evaluating the viability of applying this doping material and method in large-scale commercial production.
High critical current density (Jc) and small magnetic relaxation are crucial for technological applications of high temperature superconductors. So far, improved Jc has been reported, based on the pinning of vortices via local structural inhomogeneities in superconductors, which are induced by chemical doping, irradiation, and inclusion of non-superconducting secondary phases. In cuprates and iron-based superconductors (IBSCs), the superconducting state is induced mainly through chemical doping/substitution (x) and high pressure. Chemical doping (addition of holes or electrons) can change the lattice parameters and introduce internal chemical pressure, which modulate the electronic band structure and the density of states at the Fermi level through changes to the carrier concentration. High pressure is a well-known clean and effective tuning technique to explore superconductivity. In an IBSC, the most significant effect of high pressure is directly causing a reduction in the cell volum
Core densification in superconducting wire is highly desirable for obtaining high performance superconducting wires. Since voids hinder current flow in the superconducting core and they directly affect electrical property. In this study, we proposed a magnesium powder blending to regulate the porous properties. Our study delved deeper into the relationship between various particle parameters (such as particle size and distribution), impurities (MgO and Mg(OH)2), superconducting transition temperature, and current carrying capacity for MgB2 superconducting wires. We found a significant correlation between these factors and the porous properties. In particular, the blending of raw powders having spherical shape enables tuning of morphological structures and crystallinities inside cores of the power-in-tube processed MgB2 wires, resulting in superior superconducting properties. Our finding provides in-depth insights of methodological approaches towards more widespread use of superconducti
Here, we report superconducting Mg11B2 wires made by using the internal Mg diffusion technique with isotopic amorphous nano boron (11B) as the precursor material. We show the influence of annealing temperature and isostatic pressure of 0.1 MPa and 1.1 GPa on Mg diffusion into 11B layer, microstructure of superconducting filament, critical current density (Jc) at 20 K and 25 K, critical temperature (Tc) and irreversible magnetic induction (Birr) in mono (single-core) - and multi-filament Mg11B2 wires. Our research shows that thermal treatment at 700 °C and 0.1 MPa for 60 min yields a superconducting phase with low Tc, Birr and Jc in single-core Mg11B2 wire. A higher annealing temperature (740 °C and 0.1 MPa for 60 min) significantly accelerates the diffusion of Mg into the 11B layer and increases the Tc, Birr and Jc. However, the distribution of Mg in 11B layer is very heterogeneous (places with high and low Mg concentration). This leads to heterogeneity in the superconducting materia
Layered crystal structures of various materials form through strong in-plane covalent and weaker out-of-plane bonding. The different bonding states can lead to the appearance of anisotropies not only of electronic/electrical and magnetic properties but also of structural disorder. A deeper understanding of the disorder anisotropy is essential to carry out structural modification and to enhance the material properties. However, in the case of multi-band MgB2 superconducting materials that have layered structures, including graphene-like and six-membered rings, the nature and extent of the disorder anisotropy are not well understood. Also unknown is the influence on the transport critical current performance under magnetic fields in terms of charge-carrier scattering and vortex pinning. Herein, we have investigated the disorder anisotropy to reveal the relation with the in-field superconductivity. The MgB2 phase formed by appropriate sintering conditions with carbon doping for high trans