Growth and Characterization of $YBa_2Cu_3O_{7-δ}$ Films Deposited by Laser Ablation on $CeO_2$-Buffered Sapphire

In this work we study the growth, by pulsed laser deposition, of $YBa_2Cu_3O_{7-δ}$ (YBCO) films on the $CeO_2$-buffered R-cut sapphire substrates, with the buffer layer recrystallized prior to the deposition of superconductor. We find that the superconducting critical temperature and the critical current density of the films are very close to similar parameters for the YBCO films grown on lattice-matched single crystalline substrates. It appears that the structural defects in the buffer layer affect the microstructure of YBCO films, resulting in high values of the critical current density, suitable for applications.