Title :
Scanning Hall probe measurements on single- and double-sided sputtered YBCO films for microwave applications
Author :
Cassinese, A. ; Getta, M. ; Hein, M. ; Kaiser, T. ; Kurschner, H.G. ; Lehndorff, B. ; Muller, G. ; Piel, H. ; Skriba, B.
Author_Institution :
Fachbereich Phys., Bergische Univ., Wuppertal, Germany
fDate :
6/1/1999 12:00:00 AM
Abstract :
We have investigated the quality and the homogeneity of YBa/sub 2/Cu/sub 3/O/sub 7-x/ (YBCO) films up to /spl phi/=2" diameter and t=360 nm in thickness with a scanning Hall probe. The YBCO films were grown by high oxygen pressure sputtering with heater temperature compensation up to T=1020/spl deg/C, resulting in a constant growth temperature for both film sides. Typical /spl phi/=1" double-sided films on LaAlO/sub 3/ substrates revealed inductively T/sub c/=87.8(88.2) K and J/sub c/=4(4.5) MA/cm/sup 2/ for the first (second) deposited side. Surface resistance measurements at 87 GHz resulted in R/sub s/(4.2 K)=2.6 (1.6) m/spl Omega/. At 19 GHz, R/sub s/(4.2 K)=0.2 m/spl Omega/ with moderate field dependence up to B/sub s/=15 mT was obtained for both sides. The scanning Hall probe measurements have been carried out after cooling the film in an external magnetic field and then switching it off. The local J/sub c/ values deduced from the measured remanent induction B were in good agreement with inductive data taken at corresponding positions. Different kinds of defects and inhomogeneities were investigated with a spatial resolution of 1 mm.
Keywords :
barium compounds; critical current density (superconductivity); high-temperature superconductors; scanning probe microscopy; sputter deposition; superconducting thin films; superconducting transition temperature; surface conductivity; yttrium compounds; LaAlO/sub 3/ substrates; YBa/sub 2/Cu/sub 3/O/sub 7/; defects; double sided films; film homogeneity; inhomogeneities; microwave applications; remanent induction; scanning Hall probe; single sided films; sputtered films; surface resistance; Cooling; Electrical resistance measurement; Hall effect devices; Magnetic field measurement; Magnetic films; Sputtering; Substrates; Surface resistance; Temperature; Yttrium barium copper oxide;
Journal_Title :
Applied Superconductivity, IEEE Transactions on