Journal of Low Temperature Physics, cilt.222, sa.1, 2026 (SCI-Expanded, Scopus)
In this study, the effect of 1 mol% hexylbenzene doping on the structural, thermal, and magnetic properties of MgB2/Fe superconducting wires was investigated. Differential scanning calorimetry (DSC) showed that the additive reduced the MgB2 formation temperature, while X-ray diffraction (XRD) analysis indicated decreased crystallite size (from 51.6 to 39.9 nm) and increased microstress. The superconducting transition temperature (Tc) decreased slightly from 38.6 K to 38.2 K, accompanied by a broader transition. The critical current density (Jc) of the doped sample was one order of magnitude lower, with values of ~ 105 A/cm2 at 5 K (self-field) in the pure wire compared to ~ 104 A/cm2 in the doped one. Flux pinning analysis revealed that the normalized pinning force (Fp/Fp,max) shifted to lower fields and weakened after doping, confirming the degradation of pinning efficiency. These results demonstrate that while hexylbenzene facilitates MgB2 phase formation, it negatively affects the superconducting performance of MgB2/Fe wires.