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This study examined the impact of adding hard ferrite Ba 0.5 Sr 0.5 Fe 12 O 19 (BSF) nanoparticles to the Bi 1.8 Pb 0.4 Sr 2 Ca 2 Cu 3.2 O 10+δ (Bi, Pb)-2223) superconductor phase. The investigation specifically focused on evaluating the critical current density, fluctuation-induced conductivity, and magnetoresistance of nano-(BSF) x /(Bi, Pb)-2223 composite, where 0.00 ≤  x  ≤ 0.20 wt.%. The results revealed that the critical current density, J c , increased with the addition of nano-(BSF) up to x  = 0.04 wt.%, reaching a value of 441.20 A/cm 2 . The Aslamazov and Larkin (A–L) approach has been evaluated the fluctuation-induced conductivity. Several superconducting parameters, including coherence length ζ c (0), effective layer thickness d , penetration depth λ pd (0), and Fermi energy E F showed improvement as the concentration of nano-(BSF) increased up to x  = 0.04 wt.%. In addition to Ginzburg–Landau critical parameters, such as the thermodynamic critical field B c (0), lower critical magnetic field B c1 (0), upper critical magnetic field B c2 (0), and critical current density J c (0) demonstrated an increase up to x  = 0.04 wt.%, followed by a decrease for higher concentrations. The magnetoresistance measurements were performed at various applied DC magnetic fields, with values ranging from 0.29 to 4.44 kG, and were analyzed using the thermally activated flux creep (TAFC) and Ambegaokar–Halperin (AH) models. The calculated flux pinning energy ( U ) increased with the addition of nano-(BSF) up to x  = 0.04 wt.% and then decreased for x  > 0.04 wt.%. Furthermore, the transition width (Δ T ), was observed to increase as the applied magnetic field values increased. Moreover, the addition of nano-(BSF) increased the field-independent critical current density, J c,0 (0), up to x  = 0.04 wt.%, after which it decreased for higher concentrations.

In this study, high-density magnesium diboride (MgB2) bulk superconductors were synthesized by spark plasma sintering (SPS) under pressure to improve the field dependence of the critical current density (Jc-B) in MgB2 bulk superconductors. We investigated the relationship between sintering conditions (temperature and time) and Jc-B using two methods, ex situ (sintering MgB2 synthesized powder) and in situ (reaction sintering of Mg and B powder), respectively. As a result, we found that higher density with suppressed particle growth and suppression of the formation of coarse particles of MgB4 and MgO were found to be effective in improving the Jc-B characteristics. In the ex situ method, the degradation of MgB2 due to pyrolysis was more severe at temperatures higher than 850 °C. The sample that underwent SPS treatment for a short time at 850 °C showed higher density and less impurity phase in the bulk, which improved the Jc-B properties. In addition, the in situ method showed very minimal impurity with a corresponding improvement in density and Jc-B characteristics for the sample optimized at 750 °C. Microstructural characterization and flux pinning (fP) analysis revealed the possibility of refined MgO inclusions and MgB4 phase as new pinning centers, which greatly contributed to the Jc-B properties. The contributions of the sintering conditions on fP for both synthesis methods were analyzed.

This study investigates the feasibility of superconducting levitation for high-precision, contactless micro-assembly. Challenges in microscale manipulation, including dominant surface forces and contamination risks, necessitate innovative approaches. Using MATLAB-based dynamic simulations, we analyzed the stability, force capacity, and dynamic response of a type II superconductor levitation system, modeling flux pinning, PID-controlled positioning, and environmental disturbances. Results demonstrate excellent steady-state precision, robust disturbance rejection, and a well-defined operational load margin. Compared to acoustic and electromagnetic methods, superconducting levitation offers superior passive stability and precision, though it requires complex cryogenic operation. Technology readiness stands at TRL 2–3, with key barriers identified in cooling integration and environment sensitivity. This work establishes a quantitative foundation for advancing superconducting levitation in micro-assembly, highlighting the need for further experimental validation and integration for industrial application.

Transition to a hydrogen-based economy requires a thorough understanding of hydrogen interaction with dislocations in metals, especially in body-centered cubic (BCC) steels. Past experimental and computational investigations regarding these interactions often demonstrate two opposing results: hydrogen-induced mobility or hydrogen-induced pinning of dislocations. Through in-situ scanning electron microscopy experiments enabled by a custom-built setup, we address here this discrepancy. Our experiments reveal hydrogen-induced dislocation motion in a BCC metal at room temperature. Interestingly, however, we also observe that the same dislocations are later pinned as well, again induced by the steady hydrogen flux. Molecular dynamics simulations of the phenomena confirm the attraction of the dislocations towards the hydrogen flux, and the pinning that follows after, upon increased hydrogen trapping at the dislocation core. Future experimental or computational studies of hydrogen thus should take into account these different regimes in order to present a full picture of hydrogen defect interactions. Hydrogen affects dislocation motion in BCC metals in different ways. Using in-situ SEM and simulations, the authors observe a two-step process: hydrogen first moves dislocations, then pins them as it builds up, explaining previously conflicting results.

We have synthesized middle-entropy type REBCO (ME-REBCO) and high-entropy type REBCO (HE-REBCO) superconducting thin films with BaCeO3 artificial pins by fluorine-free metal organic deposition (FF-MOD) method and evaluated their crystallinity and superconducting properties. The c-axis orientation of crystals was confirmed by XRD analysis for all thin films. The superconducting transition temperatures in all films were over 90 K. STEM observation revealed that the crystal lattice of HE-REBCO was slightly distorted compared to a normal GdBCO film. This distortion is expected to be a “backlash” in the crystal and contribute to an increase in the allowable amounts of artificial pins. The critical current densities and flux pinning force densities at 77.3 K were enhanced by Ce doping, indicating that BaCeO3 artificial pins were introduced into the FF-MOD ME-REBCO and HE-REBCO films.

FeSe 1− x Te x superconductor has a relatively simple crystal structure and a high superconducting transition temperature in bulk form at ambient pressure, which gives it great application potential. In this study, Nb is selected to partially replace Fe in FeSe 0.4 Te 0.6 and a series of Fe 1− x Nb x Se 0.4 Te 0.6 single crystals with x  = 0, 0.01, 0.03, 0.06, and 0.1 were synthesized using the self-flux. The crystal structure and superconductivity are characterized by XRD and magnetization measurements. The fish-tail peak effect was observed in samples with x  = 0, 0.01, and 0.03. The critical current density of the three samples with x  = 0, 0.01, and 0.03 is estimated by using the Bean model. According to the Dew-Hughes model, the effect of Nb doping on the magnetic flux pinning behavior of FeSe 0.4 Te 0.6 is also investigated.

Effect of introducing nano ZrO2 particles into (Ca,Sr)CuO2 added Bi 2223 superconductor composites is studied. Microstructures revealed that 20 mol. % (Ca,Sr)CuO2 phase added to Bi 2223 formed as micron sized particles among the Bi 2223 platelet shaped grains. Distribution of (Ca,Sr)CuO2 in Bi 2223 has enhanced the critical current density (Jc) and flux pinning force density (Fp ) substantially to fields up to 9 T at 20 K. Introduction of nano ZrO2 into the composite reacted with (Ca,Sr)CuO2 particles and formed additional secondary phases of increasing amount with a rise in ZrO2 content. This resulted in lowering of Jc(0) due to a gradual reduction in the fraction of superconducting phases, but retained the enhanced field range in which flux pinning was achieved. At 10 wt.% addition of ZrO2, Bi 2223 phase was suppressed, and Bi 2212 phase was promoted. Scaling behaviour of pinning force density has shown the dominant mechanism at low fields to be normal surface pinning due to interfacial defects. The fact that (Ca,Sr)CuO2 distributes itself as fine spherical particles in Bi 2223, without causing degradation of the superconducting matrix material, is of significance and opens up a scope to optimize the microstructures further for enhancement of flux pinning.

This work presents a comparison of different commercial tapes belonging to the second-generation High-Temperature Superconductors (2G HTS) produced by SuNAM Co., Ltd., SuperOx, and Shanghai Superconductors Technology Co., Ltd. (SST) companies. The aim is to investigate pinning mechanisms responsible for best performances, looking at the anisotropy of the irreversibility field and of the flux pinning energy. The irreversibility line states the upper limit of current-carrying capacity, whereas the flux pinning energy explores the ability of material defects to act as weak collectively or strong single vortex pinning centers. All investigated samples have artificial pinning centers (APCs) included in the superconducting matrix: BHO-doped EuBCO for SST, Y2O3 in YBCO for SuperOx, and Gd2O3 particles trapped in GdBCO for SuNAM. Resistive transition curves were measured in high magnetic fields up to 16 T for magnetic field orientations parallel and perpendicular to the tape surface. We found that the anistropy of SST tape shows an overall independence both on temperature and magnetic field, while the other two samples show a more complex behavior. This leads to the conclusion that properly engineered APC optimization in coated conductors can further reduce anisotropy of superconducting properties.

The role of a layered structure in superconducting pinning properties is still at a debate. The effects of the vortex shape, which can assume for example a staircase form, could influence the interplay with extrinsic pinning coming from the specific defects of the material, thus inducing an effective magnetic field dependence. To enlighten this role, we analysed the angular dependence of flux pinning energy U(H,θ) as a function of magnetic field in FeSe0.5Te0.5 thin film by considering the field components along the ab-plane of the crystal structure and the c-axis direction. U(H,θ) has been evaluated from magneto-resistivity measurements acquired at different orientations between the applied field up to 16 T and FeSe0.5Te0.5 thin films grown on a CaF2 substrate. We observed that the U(H,θ) shows an anisotropic trend as a function of both the intensity and the direction of the applied field. Such a behaviour can be correlated to the presence of extended defects elongated in the ab-planes, thus mimicking a layered superconductor, as we observed in the microstructure of the compound. The comparison of FeSe0.5Te0.5 with other superconducting materials provides a more general understanding on the flux pinning energy in layered superconductors.

Superconducting materials offer compact and lightweight electrical devices that can significantly alter high-field magnet technology and electric power production, offering an enhanced generation of electric power and high-capacity loss-less electric power transmission. Technological uses of high-temperature superconductors (HTSC) demand high critical current density and high critical field ( H c2 ). Achieving high critical current density for Bismuth strontium calcium copper oxide (BSCCO) HTSC is challenging, so exploring the technical challenges, the factors that affect J c and the development efforts, and current research are discussed. The investigation of BSCCO HTSC discusses future advancements and innovations in BSCCO HTSC, exploring the possibilities of improved performance, broader commercialization, and new applications. Additionally, it addresses the barriers and limitations that must be overcome for BSCCO HTSC to become more widely integrated into various industries. So, the high anisotropic character of BSCCO HTSC is directly associated with these two parameters, J c and H c . One of the most commonly used techniques to increase J c values is the doping (substitution) of another element or nanoparticles, which generates artificial defects that increase flux pinning and the critical current density. This review sheds light on the basics of BSCCO superconducting materials, the key parameters, dopant roles, the industrial challenges, and the recent findings on the efforts made to improve the achievable critical current densities and overall superconducting properties for BSCCO HTSC.