Title :
Highly textured niobium films for applications in vortex-electronics
Author :
Peter, F. ; Muck, M. ; Heiden, C.
Author_Institution :
Inst. fur Schicht- und Ionentechnik, Forschungszentrum Julich, Germany
fDate :
3/1/1993 12:00:00 AM
Abstract :
Highly textured Nb-films were grown by electron-beam evaporation on sapphire substrates. The crystalline quality was examined by Rutherford-backscattering-channeling and X-ray diffraction methods. The channeling minimum yield is 2%. On c-plane sapphire the evaluation of rocking curve measurements yielded 99.98% [111] Nb // (0001) sapphire and 0.02% [110] Nb // (0001) sapphire. Measurements on microbridges with widths ranging from 2 mu m to 100 mu m (film thickness 500 nm) showed a residual resistivity ratio (R/sub 295K//R/sub 10K/) of up to 90 and critical current densities at 4.2 K and 0.2 T as low as 1.7*10/sup 4/ A/cm/sup 2/. These Nb-films form the basis for devices for local generation and detection of vortices. The writing and erasure of vortices and their detection by means of an integrated superconducting quantum interference device (SQUID) are demonstrated.<>
Keywords :
Rutherford backscattering; X-ray diffraction examination of materials; critical current density (superconductivity); electron beam deposition; flux pinning; niobium; superconducting memory circuits; superconducting thin films; surface texture; type II superconductors; vacuum deposited coatings; 4.2 K; Al/sub 2/O/sub 3/ substrate; Nb films; Rutherford-backscattering-channeling; X-ray diffraction; critical current densities; crystalline quality; electron-beam evaporation; erasure of vortices; highly textured Nb films; integrated SQUID detection; low pinning films; microbridges; residual resistivity ratio; rocking curve measurements; sapphire substrates; superconducting memories; vortex-electronics; writing of vortices; Conductivity; Critical current density; Crystallization; Current measurement; Density measurement; Niobium; SQUIDs; Substrates; Thickness measurement; X-ray diffraction;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
