In situ processed MgB2 conductors: Core densification due to mechanical deformation

We studied the effects of wire and tape shapes of in situ processed MgB2 on the critical current density (Jc), flux pinning strength, and microstructures. All samples were sintered in the temperature range of 650 degrees C-700 degrees C for 30 min. We observed that the two types of samples sintered at lower temperature, ~650 degrees C, had a relatively good high-field Jc at 4.2 K and 12 T. This can be attributed to the strong grain boundary pinning due to smaller grain size. Specifically, flat tape samples are expected to further improve the self-field Jc properties and grain connectivity due to core densification and reduction of porosity.