Akademik Veri Yönetim Sistemi
Philosophical Magazine, 2026 (SCI-Expanded, Scopus)
In this study, the effects of carbon black addition on the electrical, magnetic, and levitation properties of MgB2 superconductors produced using the SPS method were systematically investigated. Resistivity measurements were made in the 0–5 T magnetic field range for MgB2-xCx samples with different carbon contents, and the critical temperature behaviour and field dependence were evaluated. The obtained data were analysed using the WHH approach to calculate the variation of the upper critical field with temperature. Vertical (Fz) and lateral (Fx) levitation force experiments at 20 K revealed that the magnetic performance significantly decreases with increasing carbon content. Specifically, the maximum vertical levitation force ((Formula presented.)) dropped from 4.92 N for the x = 0.1 sample to 0.57 N for the x = 0.4 sample, representing an 88% reduction. Similarly, the maximum lateral force ((Formula presented.)) decreased by approximately 92%, falling from 6.38 N in the undoped sample to 0.47 N for the highest carbon concentration (x = 0.4). These quantitative results, coupled with the decline of connection quality and increased porosity, indicate that carbon black additives negatively affect macroscopic superconducting behaviour. The results suggest that carbon black is not an effective performance-enhancing additive for MgB2, but instead reduces the superconductivity and levitation properties by limiting the structural integrity.