The Effects of Structural,Thermal, and Magnetic Properties of Hexylbenzene-Doped MgB2 Superconductor

The effects of the amount of hexylbenzene additive (C₁₂H₁₈) on the structural, thermal, and magnetic properties of MgB₂ superconductor are examined in this study. Pure and hexylbenzene-doped MgB₂ bulk samples were produced with in situ solid-state reaction method. X-ray diffraction patterns of MgB₂ doped with MgB₂ and hexylbenzene at different ratios were determined to have MgB₂ as the main phase and consisted of a small amount of MgO. Pure and different ratios of hexylbenzene-doped Mg and B starting powders were heat-treated by a differential scanning calorimeter between room temperature and 800 °C. It was determined from the differential scanning calorimetry curves obtained that the first exothermic peak pointed the MgB₂ phase emerging with a solid–solid (Mg–B) reaction, and this temperature shifted towards the low temperatures as the hexylbenzene addition rates increased. It was observed that there was dependency to the applied field in all samples from the ac susceptibility measurements as a function of the temperature in pure and hexylbenzene-doped MgB₂ superconductor materials, and shift towards the lower temperatures in T _c, superconducting transition temperature, with increasing content. It was observed that the changes occurred in in-phase ((chi ^{prime })) and out-off-phase ((chi ^{prime prime })) components of ac susceptibility both weakened the MgB₂ phase structure of hexylbenzene content and, as a result of this, led to changes in the pinning mechanism.