[01] V. I. Matsui, Institute of Metal Physics, National Acad. Sci. of Ukraine, Kiev, Ukraine. [02] V. S. Flis, Institute of Metal Physics, National Acad. Sci. of Ukraine, Kiev, Ukraine. [03] V. O. Moskaliuk, Institute of Metal Physics, National Acad. Sci. of Ukraine, Kiev, Ukraine. [04] A. L. Kasatkin, Institute of Metal Physics, National Acad. Sci. of Ukraine, Kiev, Ukraine. [05] N. A. Skoryk, Institute of Metal Physics, National Acad. Sci. of Ukraine, Kiev, Ukraine. [06] V. L. Svechnikov, Institute of Metal Physics, National Acad. Sci. of Ukraine, Kiev, Ukraine.

In the present work we study a series of pulse-laser deposited (PLD) high-Tc superconductor (HTS) Y-Ba-Cu-O (YBCO) films with a different defect nano-structure and thickness, namely: (a) pristine YBCO films; (b) YBCO films with implanted Ba-Zr-O (BZO) nano-particles; multilayer YBCO – yttrium oxide (YBCO/YO) films with a sequence (5 layers) of HTS (YBCO) and dielectric phase -yttrium oxide Y-O (YO). All these films were deposited on single crystalline La-Al-O substrates by use of two-beam PLD technique. The critical current density Jc(B,T) dependencies on applied dc magnetic field and temperature for the films under study were obtained from ac susceptibility measurements with a subsequent treatment of experimental results on the base of the Clem-Sanches critical state model. Structural studies of deposited YBCO(BZO) films demonstrate extraction of impurity phase in form of nano-sized particles which are self-organized in columnar c- oriented linear ‘nanorods’ while for the multilayer YBCO/YO films formation of Y-O layers in form of aligned in (ab) - plane extended Y-O nano-particles with high value of aspect ratio (102-103) was observed. The additional defect nanostructure plays the role of strong pinning sites for Abrikosov vortices preventing their motion, thus increasing the critical current value. Moreover, this additional nanostructure, which in YBCO (BZO) films emerges in form of point-like nanoparicles or linear nanorods and in the (YBCO/YO) multylayer films as a high density (ab)-plane stacking faults can improve the current-carrying abilities of these films not only by significant increase of Jc(T,B) absolute value, but also by smoothing of its magnetic field and thickness dependencies. Obtained results distinctly demonstrate that usage of nanotechnological techniques in fabrication of HTS films and coatings allows to improve noticeably their current carrying abilities for needs of modern electric power engineering and electronics.

High-Tc Superconductor (HTS), Pulse-Laser Deposition (PLD), Abrikosov Vortex, Pinning, Critical Current

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