The Effects of Structural, Thermal, and Magnetic Properties of Hexylbenzene-Doped MgB 2 Superconductor

The effects of the amount of hexylbenzene additive (C 12 H 18 ) on the structural, thermal, and magnetic properties of MgB 2 superconductor are examined in this study. Pure and hexylbenzene-doped MgB 2 bulk samples were produced with in situ solid-state reaction method. X-ray diffraction patterns of MgB 2 doped with MgB 2 and hexylbenzene at different ratios were determined to have MgB 2 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 MgB 2 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 MgB 2 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 ( χ ^') and out-off-phase ( χ ^'' ) components of ac susceptibility both weakened the MgB 2 phase structure of hexylbenzene content and, as a result of this, led to changes in the pinning mechanism.