Enhancement in High-Field J_c Properties and the Flux Pinning Mechanism of MgB_2 Thin Films on Crystalline SiC Buffer Layers

摘要

We have studied the influence of crystalline SiC buffer layers on the critical current density and on the flux pinning mechanism in MgB_2 thin films. Crystalline SiC buffer layers were deposited on the Al_2O_3 (0001) substrates by using a pulsed laser deposition method, and then MgB_2 thin films were grown on the SiC-buffered layer by using a hybrid physical-chemical vapor deposition technique. MgB_2 thin films with crystalline SiC-buffered layers showed a significant critical current density's enhancement in the high magnetic field region. An uncommon plateau-like behavior was also observed when the normalized flux pinning force density was scaled with the reduced magnetic field. Based on the analyses of the scaling behavior of the flux pinning force, grain boundary pinning is likely to be a dominant pinning mechanism in the SiC-buffered MgB_2 thin films.