Skip to Main Content
Magnetic field and angle dependencies of critical current density Jc(H,θ) are measured for single-crystal c-oriented epitaxial YBa2Cu3O7-δ thin films with high Jc≈2 MA/cm2 at 77 K. Films are deposited by off-axis dc magnetron sputtering onto r-cut sapphire substrates buffered with CeO2. Experimental evidences of the dominant contribution of extended linear defects (growth-induced out-of-plane edge dislocations) to pinning mechanism and critical current behavior are presented. A consistent model of vortex lattice depinning from a linear defect system is developed. Detailed Jc(H) measurements start from very low fields (<0.001 T). Qualitatively different angle dependencies Jc(θ) are obtained in different field ranges. Their evolution is comprehended on the base of depinning model. The "peak-effect" observed in Jc(H)-dependencies at parallel magnetic field is discussed as a contribution of electromagnetic pinning.