Material Specification for Tl:2212; [Tl-Ba-Ca-Cu-O]
Process: Solid State Reaction
Notes: The authors cite D.S. Ginley et al., J. Crystal Growth, Vol. 91, 456 (1988), and summarize the procedure as follows. "Crystalline plates were prepared by 'pseudo-flux growth'... Our current procedure employs Tl2O3, CaO, BaO and CuO powders of at least 99.99% purity that are ground, mixed, and sieved thoroughly and then loaded directly into Pt crucibles with tight fitting Pt lids... The loaded crucibles are transferred into a vertical tube furnace that is then flushed with oxygen and maintained with an oxygen atmosphere at a pressure slightly above the local ambient atmospheric pressure throughout the growth cycle. Rapid heating (about 5 min) to 950 °C followed by a heat soak for 1 h to 2 h is achieved by moving the crucible into the preheated furnace. The temperature is then lowered over a period of 12.5 h to 700 °C and subsequently to 25 °C in 5-6 h."
Formula: Tl2Ba2CaCu2O8
Informal Name: Tl:2212
Chemical Family: Tl-Ba-Ca-Cu-O
Chemical Class: Oxide
Structure Type: Single Crystal
Manufacturer: In House
Commercial Name: In House
Production Date:
Lot Number:
Production Form:
Crystallography for Tl:2212; [Tl-Ba-Ca-Cu-O]
| Crystal System: | Tetragonal |
| Formula Units per Cell: | |
| Space Group: |
|
Cell Parameters
| Initial Ratio of Powders (Tl:Ba:Ca:Cu) |
Temp
K
|
a
Å
|
b
Å
|
c
Å
|
| 4:1:3:4 |
296 |
3.8618(4) |
-- |
29.217(7) |
| 2:2:2:3 |
296 |
3.8578(3) |
-- |
29.371(4) |
| 1:1:1:2 |
296 |
3.8588(7) |
-- |
29.437(9) |
Measurement Method: X-ray diffraction
"For our detailed crystal structure determination studies, room temperature MoKα intensities were measured over at least a hemisphere of k-space (to 2θ = 60° on a Nicolet diffractometer; of the order of 1570 and 1910 independent measurements for Tl-2122 and Tl-2223, respectively (were used)...) Our sturcture determination procedure is a...step-by-step procedure for each of the crystals... Typically, least-squares calculations, coupled with appropriate Fourier syntheses, on a simple model (would be used)..."
Cautions: Evaluated Data
Critical Temperature for Tl:2212; [Tl-Ba-Ca-Cu-O]
| Intial Ratio of Powders (Tl:Ba:Ca:Cu) |
Critical Temperature (K) |
| 4:1:3:4 |
94 |
| 2:2:2:3 |
105 |
| 1:1:1:2 |
102 |
Measurement Method: SQUID magnetometer
"Static magnetization was measured versus temperature and magnetic field in a commercial SQUID susceptometer... Most data were recorded with the magnetic field applied normal to the plates... The onset of superconductivity (T
c) was defined as that temperature below which the Meissner diagmagnetism dominated the normal state paramagnetic response."
Cautions: Evaluated Data
Material Specification for Tl:2223; [Tl-Ba-Ca-Cu-O]
Process: Flux Growth
Notes: The authors cite D.S. Ginley et al., J. Crystal Growth, Vol. 91, 456 (1988), and summarize the procedure as follows. "Crystalline plates were prepared by 'pseudo-flux growth'... Our current procedure employs Tl2O3, CaO, BaO and CuO powders of at least 99.99% purity that are ground, mixed, and sieved thoroughly and then loaded directly into Pt crucibles with tight fitting Pt lids... The loaded crucibles are transferred into a vertical tube furnace that is then flushed with oxygen and maintained with an oxygen atmosphere at a pressure slightly above the local ambient atmospheric pressure throughout the growth cycle. Rapid heating (about 5 min) to 950 °C followed by a heat soak for 1 h to 2 h is achieved by moving the crucible into the preheated furnace. The temperature is then lowered over a period of 12.5 h to 700 °C and subsequently to 25 °C in 5-6 h."
Formula: Tl2Ba2Ca2Cu3O10
Informal Name: Tl:2223
Chemical Family: Tl-Ba-Ca-Cu-O
Chemical Class: Oxide
Structure Type: Single Crystal
Manufacturer: In House
Commercial Name: In House
Production Date:
Lot Number:
Production Form:
Critical Temperature for Tl:2223; [Tl-Ba-Ca-Cu-O]
| Intial Ratio of Powders (Tl:Ba:Ca:Cu) |
Critical Temperature (K) |
| 4:1:3:10 |
111 |
| 4:1:4:8 |
107 |
Measurement Method: SQUID magnetometer
"Static magnetization was measured versus temperature and magnetic field in a commercial SQUID susceptometer... Most data were recorded with the magnetic field applied normal to the plates... The onset of superconductivity (T
c) was defined as that temperature below which the Meissner diagmagnetism dominated the normal state paramagnetic response."
Cautions: Evaluated Data
