H. Wakana et O. Michikami, Preparation of CeO2 backslash SrTiO3 bilayers as a barrier material for SIS Josephson junctions, PHYSICA C, 357, 2001, pp. 1440-1443
CeO2, SrTiO3 (STO) and CeO20\STO as barrier materials were deposited on c-a
xis-oriented EuBa2Cu3O7-delta (EBCO) films with T-c endpoints (T-ce) above
90 K, and the effects on the superconducting properties of the lower-layer
EBCO were examined. For several 100-Angstrom -thick CeO2 Sputter deposition
s, the EBCO did not deteriorate, but the CeO2 film contained many pinholes.
On the other hand, a 50-Angstrom -thick STO deteriorated an EBCO film to T
-ce = 52 K. When a CeO2\STO multi-barrier was deposited, the deterioration
of EBCO was reduced, and the generation of pinholes was suppressed. Activat
ed oxygen plasma treatment was effective for the recovery of EBCO covered b
y a CeO2\STO multibarrier. In the differential characteristics of an I-V cu
rve from a junction with a CeO2 (50 Angstrom)\STO (200 Angstrom) multibarri
er, a gap structure was observed. (C) 2001 Elsevier Science B.V. All rights
reserved.