Trapped Magnetic Field of Dense MgB2 Bulks Fabricated under High Pressure

We have measured the trapped magnetic field BT, critical current density Jc and connectivity K between crystal grains for the MgB2 bulks fabricated by a HIP method and a capsule method. The maximum BT value is 2.51 T at 12.7 K for the bulk fabricated by HIP method. From the SEM images of the bulks prepared by HIP at 98 and 980 MPa, the higher pressure enhances the grain growth. These superconducting characteristic values for the bulks by the HIP method were higher than those for the bulks by the capsule method.