Material Specification for La:21; [La(Ca)-Cu-O]
Process:
Notes: "Powders of (La1-xCax)2CuO4(LCCO) were prepared by the solid-state reaction of La2O3, CaCO3 and CuO. Powders of the three starting materials were mixed in a desired ratio, heated in air at 1000 °C for 10 h while grinding several times. The resulting powders were pelletized, further heated at 1000 °C for 10 h, and then quenched to room temperature. Annealed LCCO samples were prepared using the same procedure, treated at 500 °C under an oxygen atmosphere at 9.8 MPa for 10 h, and slowly cooled to room temperature."
Formula: La1.9Ca0.1CuO4
Informal Name: La:21
Chemical Family: La(Ca)-Cu-O
Chemical Class: Oxide
Structure Type: Polycrystalline
Manufacturer: In House
Commercial Name: In House
Production Date:
Lot Number:
Production Form:
Crystallography for La:21; [La(Ca)-Cu-O]
| Crystal System: | Orthorhombic |
| Formula Units per Cell: | 2 |
| Space Group: |
Cmca
|
Cell Parameters
| Heat Treatment () |
Temp
K
|
a
Å
|
b
Å
|
c
Å
|
| annealed |
296 |
5.34179(9) |
13.1697(2) |
5.35951(9) |
| quenched |
296 |
5.34186(9) |
13.1696(2) |
5.35931(9) |
| annealed |
18 |
5.32023(7) |
13.1238(2) |
5.37404(7) |
Atomic Coordinates
| Heat Treatment () |
Atom |
Temp
K
|
a-axis |
b-axis |
c-axis |
| annealed |
La/Ca |
296 |
0 |
0.36098(7) |
0.0050(5) |
| annealed |
Cu |
296 |
0 |
0 |
0 |
| annealed |
O(1) |
296 |
1/4 |
0.0048(3) |
1/4 |
| annealed |
O(2) |
296 |
0 |
0.1832(1) |
-0.0189(8) |
| quenched |
La/Ca |
296 |
0 |
0.36099(6) |
0.0054(5) |
| quenched |
Cu |
296 |
0 |
0 |
0 |
| quenched |
O(1) |
296 |
1/4 |
0.0048(3) |
1/4 |
| quenched |
O(2) |
296 |
0 |
0.1831(1) |
-0.0188(7) |
| annealed |
La/Ca |
18 |
0 |
0.36104(7) |
0.0075(3) |
| annealed |
Cu |
18 |
0 |
0 |
0 |
| annealed |
O(1) |
18 |
1/4 |
0.0070(2) |
1/4 |
| annealed |
O(2) |
18 |
0 |
0.1829(1) |
-0.0331(3) |
Measurement Method: Neutron diffraction
"Neutron powder diffraction data were obtained at room temperature (both samples) and at 18 ± 4 K (annealed LCCO) on the TOF neutron powder diffractometer, HRP, at the KENS pulsed spallation neutron surce. Intensity data were measured with twelve
3He counters fixed at an average diffraction angle, 2θ, of 170°. The samples were contained in a cylindrical vanadium cell (10 mm in diameter, 42 mm in length and 25 µm in thickness), which was placed in an aluminum vacuum chamber. In the room-temperature experiments, the cell was kept rotating around its axis during data collection to reduce a preferred-orientation effect. A Cryomini refrigerator was used for the low-temperature experiment. ... The structural parameters of LCCO were refined by the Rietveld method with RIETAN for TOF neutron powder diffraction."
Cautions: Evaluated Data
Critical Temperature for La:21; [La(Ca)-Cu-O]
| Heat Treatment () |
Critical Temperature (K) |
| annealed |
24 |
| quenched |
23 |
Measurement Method: Magnetization method
"Magnetization measurements showed that the T
c's of annealed and quenched LCCO were 24 K and 23 K, respectively." No additional measurement details were noted.
Cautions: Unevaluated Data
