Superconducting joint for MgB2 thin films by sol-gel method

MgB2 has shown great potential in making medium strength superconducting magnet using electronic refrigeration without liquid helium. One of the major problem in building the MgB2 superconducting magnet is the joints in the coils. An effective method of building a superconducting joint is crucial. In this work, we have demonstrated a novel process of building a superconducting joint utilizing sol-gel method. Two HPCVD MgB2 thin film on SiC substrate is pasted face-to-face with Mg(BH4)2
- Et2O gel. After annealing in Mg vapor, Mg(BH4)2
- Et2O gel decomposed and turned to MgB2 superconducting joint. The joint showed good connectivity between the two films and has a good TC of 34 K. Infield measurement of the joint showed that the joint work well at 20 K with the applied magnetic field up to 4 T.