Akademik Veri Yönetim Sistemi
Journal of Superconductivity and Novel Magnetism, cilt.30, sa.7, ss.1727-1736, 2017 (SCI-Expanded)
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 Tc, 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 MgB2 phase structure of hexylbenzene content and, as a result of this, led to changes in the pinning mechanism.