Superconducting properties of C-doped MgB2 thin film fabricated by the precursor and post-annealing method using the PLD process

The superconducting properties and microstructures of carbon-doped MgB2 thin films have been investigated. Carbon substitution of the boron site is an effective way to enhance the upper critical fields Hc2. Carbon-doped MgB2 films were fabricated using different carbon source targets, such as ethyltoluene and SiC, during the deposition process. The transition temperatures of carbon-doped thin films were lower than those of non-doped thin films. The Jc values of carbon-doped films were not as high as those of non-doped films. One of the reasons for the Jc suppression was the coarsening of MgB2 grains and the increase of impurities at grain boundaries.