Title :
Thickness dependence of critical currents and depth profiling of transport properties in high rate in-situ grown YBa2Cu3O7-x films
Author :
Jo, W. ; Ohnishi, T. ; Huh, J.U. ; Hammond, R.H. ; Beasley, M.R.
Author_Institution :
Geballe Lab. for Adv. Mater., Stanford Univ., CA, USA
fDate :
6/1/2003 12:00:00 AM
Abstract :
YBa2Cu3O7-x (YBCO) films are grown by in-situ electron beam evaporation at high deposition rates (100∼350 Å/sec). The YBCO films are found to consist of two regions as a function of thickness: a region on the bottom with defect-free microstructure reflecting layer-by-layer growth and at the top a defected type reflecting island-growth. We suggested a new phase stability to explain this growth behavior, with Ba-Cu-O liquid fluxes. The films show critical current density greater than 2 MA/cm2 on crystal substrates. Depth profiling of the transport properties (critical current density and resistivity) has been performed by etching the layers, elucidating that it is the island-growth layer where high critical current density is being carried.
Keywords :
barium compounds; critical current density (superconductivity); electrical resistivity; electron beam deposition; high-temperature superconductors; superconducting thin films; yttrium compounds; YBCO film; YBa2Cu3O7; critical current density; depth profiling; electrical resistivity; electron beam evaporation; high temperature superconductor; island growth; layer-by-layer growth; microstructure; phase stability; thickness dependence; transport properties; Conductive films; Conductivity; Conductors; Critical current density; Electron beams; Etching; Microstructure; Optical films; Substrates; Yttrium barium copper oxide;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
DOI :
10.1109/TASC.2003.812015