Angular dependence of tunneling effects in Ba{sub 1{minus}x}K{sub x}BiO{sub 3} grain boundaries

Book · Sat Dec 31 04:00:00 EST 1994

OSTI ID:64716

Kussmaul, A; Hellman, E S; Hartford, Jr, E H ^[1]; Gupta, A ^[2]; Tedrow, P M ^[3]

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1. AT and T Bell Labs., Murray Hill, NJ (United States)
2. IBM T.J. Watson Research Center, Yorktown Heights, NY (United States)
3. Francis Bitter National Magnet Lab., Cambridge, MA (United States)

The authors report on the tunneling properties of Ba{sub 1{minus}x}K{sub x}BiO{sub 3} (BKBO) grain boundaries prepared on bicrystal substrates. They studied symmetric tilt boundaries with 5{degree}, 24{degree}, 36.8{degree} and 45{degree} misorientation on SrTiO{sub 3}, and 24{degree} on MgO substrates. The three high angle misorientations used yield clear superconductor-insulator-superconductor behavior, with very little conductance below the bias corresponding to twice the BKBO energy gap, and a strong peak at that value. The two samples prepared on MgO yielded somewhat broader tunneling characteristics, but otherwise similar features compared to the samples prepared on SrTiO{sub 3}; they showed the lowest junction resistivity and the weakest conductance increase at high bias. The linear conductance background consistently observed in superconductor-insulator-normal metal junctions is absent in the grain boundary junctions. For the 5{degree} samples, they observe weak link behavior below {Tc}, with a critical current density of 65A/cm{sup 2}. A similar angular dependence is seen in Nd{sub 1.85}Ce{sub 0.15}CuO{sub 4{minus}{delta}}.

• OSTI ID: 64716
• Report Number(s): CONF-940142--; ISBN 0-8194-1453-0
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
66 PHYSICS
BARIUM OXIDES
BISMUTH OXIDES
CERIUM OXIDES
COPPER OXIDES
EXPERIMENTAL DATA
GRAIN BOUNDARIES
GRAIN ORIENTATION
HIGH-TC SUPERCONDUCTORS
MAGNESIUM OXIDES
NEODYMIUM OXIDES
POTASSIUM OXIDES
STRONTIUM TITANATES
SUPERCONDUCTING JUNCTIONS
TRANSITION TEMPERATURE
TUNNEL EFFECT