The Investigation of In-Situ Processed MgB <sub>2</sub> on Bulk Electromagnetic Behaviour by Numerical and Experimental Methods

A systematic study was reported on the influence of the sintering temperatures on the bulk electromagnetic properties, such as levitation force, trapped field and flux pinning mechanism of MgB2 samples, via both experimental and numerical methods in addition to the microstructural properties. The maximum levitation and guidance force values increase with increasing sintering temperature from 700 to 775 °C and then decrease for the sample sintered at 850 °C. At higher fields, the bigger pinning force density of the sample sintered at 700°C can be attributed that the Mg particles are more effective to act as pinning centres inside the MgB2 sample than that of MgO particles at higher magnetic field region of about 0.7 T. The consistency of numerical trapped flux values with the Jφ bulk supercurrent density inside the samples and the experimental trapped flux results in literature indicates the success of the numerical modelling performed in this study. In this study, two types of pinning mechanism for high and low field regions were determined for pure MgB2 samples. The experimental results of this study clearly show that the optimum sintering temperature is an effective process to obtain high levitation capability and trapped field in especially pure bulk MgB2 material. It can be additionally said that the numerical results are useful to understand the physical background of the intrinsic pinning mechanism in pure MgB2 and so to fabricate tailored doped MgB2 superconducting samples with enhanced electromagnetic properties.