https://doi.org/10.1007/s100510170311
Nanosize patterns as reference structures for macroscopic transport properties and vortex phases in YBCO films
1
INFM - UdR Torino-Politecnico; INFN - Sez. Torino,
Politecnico di Torino, c.so Duca degli Abruzzi 24, 10129 Torino, Italy
2
Istituto di Cibernetica del Consiglio Nazionale delle Ricerche,
Via Toiano 6, 80072 Arco Felice, Italy
3
PaSTIS-CNRSM, SS 7 Appia km.712, 72100 Brindisi, Italy
Corresponding author: a mezzetti@polito.it
Received:
16
October
2000
Revised:
28
November
2000
Published online: 15 February 2001
This paper reports on the striking correlation between nanosize mosaic domain walls
in YBCO films and 1D
rows of parallel Josephson junctions, determining the curves.
From X-ray data analysis, it results that the
average "hidden" domain wall, faceted at a nanometric scale, is almost mimicking the
Josephson Junction (JJ) 1D array. The assumption that the JJs and the domain-wall arrays
are coincident, enables to find out the particular scaling field, making the
curves
independent of temperature. This scaling field can be interpreted in terms of the Josephson nature
of the transport current across these particular patterns in the intermediate temperature range.
By means of our model it is also possible to calculate two asymptotic behaviors of the pinning force
as a function of field, for low and high fields, respectively. These behaviors are punctually repeated
by the
experimental results in the same asymptotic limit, so that two corresponding vortex regimes
are clearly pointed out. All results can be interpreted by concluding that in the intermediate temperature
range, the strong pinning observed in high quality YBCO films is due to the Josephson Junctions average
patterns. These patterns are the counterpart related to the transport mechanisms of "hidden" structural
nano-domains.
PACS: 74.76.Bz – High-Tc films / 74.60.Jg – Critical currents / 74.50.+r – Proximity effects, weak links, tunneling phenomena, and Josephson effects / 74.60.Ge – Flux pinning, flux creep, and flux-line lattice dynamics
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2001