Material Specification for LaBa:347; [La-Ba(Ca)-Cu-O]
Process: Solid State Reaction
Notes: "All chemicals were of 99.9% purity. La2O3 was preheated at 1000 °C for 10 h. Others were used as received. A series of samples with nominal compositions of La3CaxBa4-xCu7Oy (x=0-4.00) was prepared from appropriate mixtures of La2O3, CaCO3, BaCO3 and CuO powders. They were calcined for 6 h in air at 1000 °C in an alumina boat, with one intermittent grinding. They were then pressed into pellets, and sintered in flowing N2 at 900 °C or 950 °C for 8-16 h, annealed in flowing O2 atmosphere at 900 °C or 950 °C for 8 h, cooled to 400 °C, reannealed for 3 h and then cooled to room temperature in the furnace. If any impurity was detected by the XRD analysis, the sample was resintered and reannealed again."
Formula: La3Ba4-xCaxCu7Oy
Informal Name: LaBa:347
Chemical Family: La-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 LaBa:347; [La-Ba(Ca)-Cu-O]
| Crystal System: | Tetragonal |
| Formula Units per Cell: | |
| Space Group: |
|
Cell Parameters
| x of Cax (formula units) |
Temp
K
|
a
Å
|
b
Å
|
c
Å
|
| 0.0 |
296 |
3.915 |
-- |
-- |
| 0.1 |
296 |
3.912 |
-- |
-- |
| 0.2 |
296 |
3.907 |
-- |
-- |
| 0.3 |
296 |
3.900 |
-- |
-- |
| 0.4 |
296 |
3.898 |
-- |
-- |
| 0.5 |
296 |
3.893 |
-- |
-- |
| 0.75 |
296 |
3.882 |
-- |
-- |
| 1.0 |
296 |
3.879 |
-- |
-- |
| 1.25 |
296 |
3.872 |
-- |
-- |
Measurement Method: X-ray diffraction
"The XRD analysis was taken on a Rigaku 18 kW rotating anode diffractometer... Unit cell parameter analyses by the Treor method showed that all the triple-perovskite phases found in these materials had a tetragonal symmetry. The a- and c-axis lengths were decreased with increasing x value, which was due to the introduction of the smaller Ca-atoms in the formula."
Cautions: Evaluated Data
Values for the c-axis were not reported.
Digitized data were obtained from Figure 3 of the paper.
Critical Temperature for LaBa:347; [La-Ba(Ca)-Cu-O]
| x of Cax (formula units) |
Tc (onset) (K) |
Critical Temperature (K) |
| 0.0 |
48 |
38 |
| 0.1 |
49 |
35 |
| 0.2 |
50 |
36 |
| 0.3 |
53 |
36 |
| 0.4 |
57 |
36 |
| 0.5 |
65 |
48 |
| 0.75 |
76 |
66 |
| 1.0 |
84 |
80 |
| 1.1 |
86 |
82 |
| 1.2 |
85 |
81 |
| 1.25 |
84 |
80 |
Measurement Method: Four-probe method
"The AC resistivity was measured by a four-probe configuration with a Linear Research LR-400 ohmmeter, and the temperature was measured by a 0.07% Fe-doped Au versus Chromel thermocouple near the sample."
Cautions: Evaluated Data
Digitized data were obtained from Figure 4 of the paper.
Magnetic Susceptibility for LaBa:347; [La-Ba(Ca)-Cu-O]
| x of Cax (formula units) |
Magnetic Susceptibility (arbitrary) |
| 0 |
-1.53 |
| 0.10 |
-2.84 |
| 0.20 |
-3.10 |
| 0.30 |
-4.72 |
| 0.40 |
-7.73 |
| 0.50 |
-8.95 |
| 1.00 |
-13.0 |
| 1.50 |
-14.4 |
| 2.00 |
-12.5 |
| 2.50 |
-5.80 |
| 3.00 |
-0.20 |
| 3.50 |
-0.10 |
Measurement Method: SQUID magnetometer
"The DC magnetic susceptibility (shielding effect) was recorded with a Quantum Design SQUID magnetometer on the sintered pellets at (1 mT = 10 G) magnetic fields."
Cautions: Evaluated Data
