Sefrioui, ZouhairArias Serna, DiegoMorales, F.Varela Del Arco, MaríaLeón Yebra, CarlosEscudero, R.Santamaría Sánchez-Barriga, Jacobo2023-06-202023-06-202001-01-010163-182910.1103/PhysRevB.63.054509https://hdl.handle.net/20.500.14352/59642© 2001 The American Physical Society. Z.S. gratefully acknowledges financial support from Agencia Española de Cooperación Internacional (AECI). Financial support from CICYT Grant Nos. MAT94-0604, MAT97-0675, and MAT99-1706E is also acknowledged. F.M. and R.E. acknowledge financial support from DGSCAUNAM and CONACyT- MEXICO.We report on transport and magnetic relaxation measurements of deoxygenated YBa_(2)Cu_(3)O_(7-δ) thin films. Strongly oxygen depleted samples with δ=0.6 are produced to ensure the pure two-dimensional nature of the vortex system. Linear resistivity shows a temperature dependence according to ρ_(lin^(α))exp[-((T_(0)/T)^(p)]. T_(0) takes a value of 230±10 K over the whole field range, and p changes from 1±0.03 at 2 T to 0.70±0.03 at 8 T. For fields higher than 4 T, dissipation in the linear regime (low current densities) is dominated by quantum variable range hopping ~VRH! of vortices. At high current densities and low temperatures, nonlinear dissipation takes place by quantum creep, characterized by a temperature-independent resistivity and by a saturation of the magnetic relaxation rate.engjournal articlehttp://dx.doi.org/10.1103/PhysRevB.63.054509http://journals.aps.org/open access537Ultrathin superconducting filmsGlass phase-transitionQuantum creepMagnetic-relaxationII superconductorsT-G=0 KVorticesTransport.ElectricidadElectrónica (Física)2202.03 Electricidad