Tunneling spectroscopy of heavily underdoped crystals of Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+{delta}}

Conference · Thu Feb 17 04:00:00 EST 2000

OSTI ID:751866

Ozyuzer, L; Zasadzinski, J F; Miyakawa, N; Kendziora, C; Jian, S; Hinks, D G; Gray, K E

Crystals of Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+{delta}} with optimal {Tc} = 95 K have been underdoped using two different methods and the superconducting gaps have been obtained by tunneling. In some cases, three different tunneling geometries have been utilized: point contact, STM and break junctions. The first doping method involves control of the oxygen content by annealing in various partial pressures of oxygen. These crystals exhibit a narrow spread of gap values over a wide doping range from overdoped ({Tc} = 56 K) to underdoped with {Tc} = 70 K. However, for underdoped crystals with {Tc} midpoints in the range 25 K--63 K, there is a dramatic increase in the spread of gap values which may signal the development of static phase separation of either chemical or electronic origin. To avoid possible chemical phase separation, the authors have explored another doping procedure which incorporates Dy substitution on the Ca site. These crystals exhibit a relatively narrow superconducting transition width and some preliminary tunneling spectra will be presented.

• Research Organization: Argonne National Lab., IL (US)
• Sponsoring Organization: US Department of Energy (US)
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 751866
• Report Number(s): ANL/MSD/CP-100813
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BISMUTH OXIDES
CALCIUM OXIDES
COPPER OXIDES
CRYSTAL DOPING
DYSPROSIUM OXIDES
ENERGY GAP
HIGH-TC SUPERCONDUCTORS
STRONTIUM OXIDES
SUPERCONDUCTIVITY
TRANSITION TEMPERATURE