Superconducting and levitation force characterisation of pyrene added MgB2 bulk superconductors

摘要

This research presents the influence of pyrene (C16H10) addition (0, 2, 4, 6, 8, 10 wt%) on the superconducting properties of bulk MgB2. For C16H10 added MgB2 samples, a shrinkage in a-lattice parameters was determined, whereas c-lattice parameters remained practically unchanged. The (110) peak observed at 2 theta approximate to 59.9 degrees slightly shifted to higher angles, the lattice strain increased and the crystallite size reduced after C16H10 addition. By virtue of induced stronger pinning force, the in-field critical current density (J(c)) increased after C16H10 addition. The J(c) value at 20 K and 4 T was obtained about two times higher (8.54 x 10(3) A/cm(2)) for 4 wt% C16H10 added MgB2 sample than that of the pure one. In addition, the variation of levitation force characteristic of MgB2 with increasing C16H10 content was determined at 20, 25 and 30 K. The best vertical levitation force performance in zero-field-cooled regime was obtained as 7.09 N/g at 20 K for 4 wt% C16H10 added MgB2 sample with 13 mm in diameter.