Material Specification for Tl:2234; [Tl-Ba-Ca-Cu-O]
Process: Solid State Reaction
Notes: "Three samples... were prepared... using Tl2O3, BaO2, CaO and CuO, mixed, milled and die-pressed into pellets. The pellets were placed in a gold tube under oxygen at (100 kPa = 1 bar), the gold tube was crimped shut and placed in a furnace at 896 °C under flowing oxygen. The temperature was immediately reset to 848 °C and the samples were reacted for 2 h then quenched to room temperature... They were subjected to anneals in various oxygen partial pressures followed by quenching in liquid nitrogen to control the oxygen stoichiometry, and they were sealed in evacuated quartz tubes to examine the effect of prolonged anneals in vacuo."
Formula: Tl2-xBa2Ca3+xCu4O12-y
Informal Name: Tl:2234
Chemical Family: Tl-Ba-Ca-Cu-O
Chemical Class: Oxide
Structure Type: Polycrystalline
Manufacturer: In House
Commercial Name: In House
Production Date:
Lot Number:
Production Form:
Crystallography for Tl:2234; [Tl-Ba-Ca-Cu-O]
| Crystal System: | Tetragonal |
| Formula Units per Cell: | |
| Space Group: |
I4/mmm |
Cell Parameters
| x of Tl2-x (formula units) |
Temp
K
|
a
Å
|
b
Å
|
c
Å
|
| 0.0 |
296 |
3.852(1) |
-- |
41.99(1) |
| 0.25 |
296 |
3.851(1) |
-- |
42.00(1) |
| 0.5 |
296 |
3.851(1) |
-- |
42.01(1) |
Measurement Method: X-ray diffraction
"X-ray diffraction patterns (were obtained using) CoK
α (radiation)." No additional measurement details were noted.
Cautions: Unevaluated Data
Critical Temperature for Tl:2234; [Tl-Ba-Ca-Cu-O]
| Critical Temperature (K) |
| 114 |
Measurement Method: Ac susceptibility
No method details were noted.
Cautions: Unevaluated Data
"...the ac susceptibility curves for the samples with nominal Ca-excess of x=0 and of x=0.5 (were determined)....The latter (x=0.5) shows a single sharp superconducting transition....The former (x=0) shows two major transitions, one at 113 K, the other at 119 K..."
Irreversibility Field for Tl:2234; [Tl-Ba-Ca-Cu-O]
| Temperature (K) |
Irreversibility Field (T) |
| 70 |
0.62 |
| 71 |
0.58 |
| 77 |
0.45 |
| 81 |
0.38 |
| 80 |
0.32 |
| 84 |
0.31 |
| 86 |
0.25 |
| 88 |
0.16 |
| 93 |
0.17 |
| 98 |
0.14 |
| 100 |
0.06 |
| 104 |
0.04 |
| 107 |
0.03 |
| 113 |
0.00 |
Measurement Method: Vibrating sample magnetometer
"The samples were investigated by... DC magnetisation using a PAR vibrating sample magnetometer... the irreversibility lines (were)... determined from the collapse of magnetisation loops..." No additional measurement details were noted.
Cautions: Evaluated Data
Digitized data were obtained from Figure 5 of the paper.
