Eur. Phys. J. B 19, 357-362 (2001)
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

Abstract

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.