M. Inoue et al., A STUDY ON THE CONTROL OF THE MATERIAL PROPERTIES OF BI2SR2CACU2OX THIN-FILMS FOR INTRINSIC JOSEPHSON-JUNCTIONS, Physica. C, Superconductivity, 307(3-4), 1998, pp. 221-228
We investigated the annealing conditions to observe intrinsic Josephso
n effects using Bi-cuprate superconductor thin films. We fabricated a
mesa structure using as-grown and annealed Bi2Sr2CaCu2Ox (Bi-2212) thi
n films and measured their electrical properties along the c-axis. Con
sequently, we succeeded in fabricating intrinsic Josephson junctions u
sing Bi-2212 thin films by means of a two-step annealing procedure, wh
ich is a combination of a high-temperature annealing in O-2 and a low-
temperature annealing in N-2. By this annealing method, the grain size
changed over the range from 0.02 mu m to more than 5 mu m in diameter
and the critical temperature T-c could be controlled in the range of
72-85 K. The critical current density along the c-axis, J(cc), was als
o controlled in the range of 10(4)-10(1) A/cm(2). The temperature depe
ndence of the resistivity of the mesa with reduced J(cc) was semicondu
ctor-like above T-c. The current-voltage (I-V) characteristics exhibit
ed clear hystereses and multiple branches, and the observed voltage ju
mp was 3-20 mV. (C) 1998 Elsevier Science B.V. All rights reserved.