Title :
Investigation of Nd-Ce-Cu-O planar tunnel junctions and bicrystal grain boundary junctions
Author :
Woods, S.I. ; Katz, A.S. ; Kirk, T.L. ; de Andrade, M.C. ; Maple, M.B. ; Dynes, R.C.
Author_Institution :
Dept. of Phys., California Univ., San Diego, La Jolla, CA, USA
fDate :
6/1/1999 12:00:00 AM
Abstract :
We have fabricated planar c-axis Pb/NCCO junctions and in-plane NCCO bicrystal grain boundary junctions. The Pb/NCCO junctions exhibit single-step elastic tunneling and sustain hysteretic Josephson supercurrents, evidence that NCCO has an s-wave component to its superconducting order parameter. Tunneling spectroscopy on high-resistance Pb/NCCO junctions reveals a semi-gap of 3-4 meV in the density of states of NCCO and evidence for phonon coupling to NCCO quasiparticles. The grain boundary junctions were made by laser ablating thin NCCO films onto yttrium-stabilized-zirconia bicrystal substrates and sustain supercurrents that modulate in applied magnetic field and show resistively-shunted-junction I-V characteristics.
Keywords :
Josephson effect; bicrystals; cerium compounds; grain boundaries; high-temperature superconductors; neodymium compounds; superconducting energy gap; superconductive tunnelling; I-V characteristics; Josephson supercurrent; NCCO thin film; Nd-Ce-Cu-O planar tunnel junction; Pb-NdCeCuO; YSZ substrate; bicrystal grain boundary junction; density of states; elastic tunneling; hysteresis; laser ablation; magnetic field modulation; phonon coupling; quasiparticles; resistively shunted junction; semi-gap; superconducting order parameter; tunneling spectroscopy; Grain boundaries; Hysteresis; Josephson junctions; Magnetic films; Magnetic modulators; Phonons; Spectroscopy; Superconducting films; Tunneling; Yttrium;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
