Material Specification for Bi:2212; [Bi-Sr-Ca(Y)-Cu-O]
Process: Melt Processed
Notes: "The crystals were grown from a powder charge comprised of Bi2O3, SrCo3, CaCO3, Y2O3, and CuO. The starting composition was stoichiometric [Bi]:[Sr]:([Ca]+[Y]):[Cu]=2:2:1:2; the relative amount of [Y]:[Ca] ranged from 0:1 to 1:0. Additionally, an extra 20-50% of CuO was... often, but not always, used as a flux to facilitate large crystal growth... once measured and manually mixed, the powder charge (typically 200-300 g total mass) was put into a high-purity alumina crucible. It was then placed in the furnace and heated in about 4 h to 1020 °C. The charge was maintained at this temperature until all of the powders had melted, a period of roughly 6 h. The cool down did not begin until a visual inspection of the crucible... revealed a totally homogeneous... and slightly viscous fluid. The mixture was then stirred with an alumina rod to insure the homogeneity of the melt... The cooldown began at 1020 °C and continued to 840 °C at a range of 1.6°/h, a process which takes just over 4 days. From 840 °C, the crucible was cooled much more quickly (approximately 10 °C/h) down to room temperature. The tendency of these crystals to cleave perpendicular to the c axis was exploited... to prepare thin, high-quality single crystals..."
Formula: Bi2Sr2Ca1-xYxCu2O8
Informal Name: Bi:2212
Chemical Family: Bi-Sr-Ca(Y)-Cu-O
Chemical Class: Oxide
Structure Type: Single Crystal
Manufacturer: In House
Commercial Name: In House
Production Date:
Lot Number:
Production Form:
Crystallography for Bi:2212; [Bi-Sr-Ca(Y)-Cu-O]
| Crystal System: | |
| Formula Units per Cell: | |
| Space Group: |
|
Cell Parameters
| 2[Y]/[Sr] (no unit) |
Temp
K
|
a
Å
|
b
Å
|
c
Å
|
| 0.00 |
296 |
-- |
-- |
30.85 |
| 0.22 |
296 |
-- |
-- |
30.56 |
| 0.33 |
296 |
-- |
-- |
30.47 |
| 0.36 |
296 |
-- |
-- |
30.49 |
| 0.39 |
296 |
-- |
-- |
30.47 |
| 0.43 |
296 |
-- |
-- |
30.34 |
| 0.44 |
296 |
-- |
-- |
30.37 |
| 0.50 |
296 |
-- |
-- |
30.42 |
| 0.51 |
296 |
-- |
-- |
30.41 |
| 0.56 |
296 |
-- |
-- |
30.31 |
| 0.56 |
296 |
-- |
-- |
30.28 |
| 0.69 |
296 |
-- |
-- |
30.13 |
| 0.69 |
296 |
-- |
-- |
30.17 |
| 0.70 |
296 |
-- |
-- |
30.22 |
| 0.74 |
296 |
-- |
-- |
30.19 |
| 0.77 |
296 |
-- |
-- |
30.10 |
| 0.81 |
296 |
-- |
-- |
30.03 |
Measurement Method: X-ray diffraction
"We have measured the c-axis modulation with Y concentration using a four-cricle diffractometer and cleaved crystals. The x rays used were from the Kα line (8.847
σ
-1) of a rotating Molybdenum anode." No additional measurement details were noted.
Cautions: Evaluated Data
Digitized data were obtained from Figure 3 of the paper.
Hall Coefficient for Bi:2212; [Bi-Sr-Ca(Y)-Cu-O]
| Nominal x of Yx (formula units) |
Measured x of Yx (formula units) |
Carrier Density (1020 cm-3) |
Hall Coefficient (mm3 /C) |
| 0 |
0 |
35.0 |
1.8 |
| 0.09 |
0.30 |
13.0 |
4.8 |
| 0.12 |
0.44 |
6.9 |
9.1 |
| 0.20 |
0.55 |
3.5 |
18.0 |
| 1.00 |
0.86 |
0.064 |
1000.0 |
Measurement Method: Hall-effect measurements
"... very thin, regularly shaped single crystals were prepared. Typical dimensions were 1 mm x 0.5 mm x 1 µm... the smallest dimension being along the crystallographic c axis. Electrical contacts were made using 12-µm-diam gold wires and silver epoxy fired at 600 °C. Contact resistances were typically less than 1Ω... two line contacts (for current) and three point contacts (for voltage) were attached... A (7 T = 70 kG) magnetic field was applied parallel to the c axis. At a given temperature and current, the samples were repeatedly rotated in the magnetic field by 180° and voltage readings were taken... All values presented were measured at 300 K."
Cautions: Evaluated Data
