Sefrioui, ZouhairArias Serna, DiegoMorales, F.Varela del Arco, MaríaLeón Yebra, CarlosEscudero, R.Santamaría Sánchez-Barriga, Jacobo2023-06-202023-06-202001-01-011) A.O. Caldeira, A.J. Leggett, Phys. Rev. Lett., 46, 211 (1981). 2) A.C. Mota, A. Pollini, P. Visani, K.A. Mïller, J.G. Bednorz, Phys. Rev. B, 36, 4011 (1987). 3) A.J.J. van Dalen, R. Griessen, S. Libbrecht, Y. Bruynseraede, E. Osquiguil, Phys. Rev. B, 54, 1366 (1996). 4) A.F.Th Hoekstra, R. Griessen, A.M. Testa, J. el Fattahi, M. Brinkmann, K. Westerholt, W.K. Kwok, G.W. Crabtree, Phys. Rev. Lett., 80, 4293 (1998). 5) L.Y. Glazman, N.Ya. Fogel, Fiz. Nizk. Temp., 10, 95 (1984), [Sov. J. Low Temp. Phys., 10, 51 (1984)]. 6) Y. Liu, D.B. Haviland, L.I. Glazman, A.M. Goldman, Phys. Rev. Lett., 68, 2224 (1992). 7) D. Ephron, A. Yazdani, A. Kapitulnik, M.R. Beasley, Phys. Rev. Lett., 76, 1529 (1996). 8) J.A. Chervenak, J.M. Valles, Jr., Phys. Rev. B, 54, R15, 649 (1996). 9) By linear regime it is understood that the average ratio of electric field (E) to current density (J) is identical to its differential value, i.e., the resistivity r is: r5E/J5dE/dJ. 10) T. Stein, G.A. Levin, C.C. Almasan, D.A. Gajewski, M.B. Maple, Phys. Rev. Lett., 82, 2955 (1999). 11) G. Blatter, V.B. Geshkenbein, V.M. Vinokur, Phys. Rev. Lett., 66, 3297 (1991). 12) M.V. Feigel’man, V.B. Geshkenbein, A.I. Larkin, V.M. Vinokur, Phys. Rev. Lett., 63, 2303 (1989). 13) G. Blatter, M.V. Feigel’man, V.B. Geshkenbein, A.I. Larkin, V.M. Vinokur, Rev. Mod. Phys., 66, 1125 (1994), Section II.A.5, Eqs. 2.103 and 2.106. 14) M.P.A. Fisher, T.A. Tokuyasu, A.P. Young, Phys. Rev. Lett., 66, 2931 (1991). 15) D.S. Fisher, M.P.A. Fisher, D.A. Huse, Phys. Rev. B, 43, 130 (1991). 16) Z. Sefrioui, D. Arias, M. Varela, M.A. López de la Torre, C. León, G. Loos, J. Santamaría, Europhys. Lett., 48, 679 (1999). 17) Z. Sefrioui, D. Arias, M. Varela, J.E. Villegas, M.A. López de la Torre, C. León, G. Loos, J. Santamaría, Phys. Rev. B, 60, 15, 423 (1999). 18) The term pure 2D refers to a system in which the vortex correlation length in the c direction is comparable to the CuO_(2) planes separation, as opposed to quasi-2D systems, in which this length is smaller than sample thickness but larger than interplane distance. See Ref. 17. 19) C. Dekker, P.J.M. Wöltgens, R.H. Koch, B.W. Hussey, A. Gupta, Phys. Rev. Lett., 69, 2717 (1992). 20) B.I. Shklovskii, A.L. Efros, Electronic Properties of Doped Semiconductors (Springer, Berlin, 1984). 21) A.I. Larkin, Yu.N. Ovchinnikov, J. Low Temp. Phys., 34, 409 (1979). 22) D. Prost, L. Fruchter, I.A. Campbell, N. Motohira, M. Konczykowski, Phys. Rev. B, 47, R3457 (1993). 23) J. Tejada, E.M. Chudnovsky, A. García, Phys. Rev. B, 47, 11, 552 (1993). 24) H.H. Wen, H.A. Radovan, F.M. Kamm, P. Ziemann, S.L. Yan, L. Fang, M.S. Si, Phys. Rev. Lett., 80, 3859 (1998).0163-182910.1103/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