Imaging Current Percolation and Ac Losses in Artificially Granular YBCO Thin Films

Author

Bartolomé, E. ; Navau, C. ; Sánchez, A. ; Chen, D.-X. ; Puig, T. ; Obradors, X. ; Cambel, V.

Author_Institution

Univ. Autonoma de Barcelona (UAB), Barcelona

Volume

17

Issue

2

fYear

2007

fDate

6/1/2007 12:00:00 AM

Firstpage

3223

Lastpage

3226

Abstract

The magnetic effects of granularity in YBCO tapes are investigated using model granular systems. Numerical simulations of the field profile, current distribution and AC susceptibility in simple granular configurations have been carried out under a critical-state, magnetic energy minimization approach. Experimentally, an artificially patterned "multigranular" YBCO epitaxial thin film has been fabricated and used to investigate the geometry-related magnetic effects of granularity. High-resolution Hall probe microscopy measurements have allowed us imaging the evolution of the magnetization distribution with the applied field, and deduce the circulation of inter- and intragranular critical-currents. AC-susceptibility measurements up to high driving-fields evidenced that AC losses arise mainly from dissipation at the artificial "grain boundary" network.

Keywords

Hall effect; barium compounds; critical currents; current distribution; grain boundaries; granular superconductors; high-temperature superconductors; magnetic susceptibility; magnetisation; percolation; superconducting epitaxial layers; superconducting tapes; yttrium compounds; YBa₂Cu₃O₇; ac losses; ac susceptibility; artificial grain boundary network; artificially patterned multigranular epitaxial thin film; current distribution; current percolation; driving field; high-resolution Hall probe microscopy; inter critical currents; intragranular critical currents; magnetic energy minimization; magnetization distribution; numerical simulations; tapes; Current distribution; Hall effect devices; Magnetic field measurement; Magnetic films; Magnetic force microscopy; Magnetic susceptibility; Numerical simulation; Semiconductor process modeling; Transistors; Yttrium barium copper oxide; Ac susceptibility; Hall probe imaging; YBCO; grain boundaries; high-temperature superconductors;

fLanguage

English

Journal_Title

Applied Superconductivity, IEEE Transactions on

Publisher

ieee

ISSN

1051-8223

Type

jour

DOI

10.1109/TASC.2007.897985

Filename

4278049