Material Specification for Y:124; [Y(Ca)-Ba-Cu-O]
Process: Solid State Reaction
Notes: "Citrate gel percursor material for the fabrication of Y1-xCaxBa2Cu4Oy ceramic superconductors with x=0, 0.05 and 0.10 was made by gelation of the respective cations with citric acid and ethanediol in water-ethanol mixtures. Depending on the composition of the desired oxidic compounds 3.2850, 3.4675 and 3.6500 g, respectively, (0.009, 0.0095 and 0.01 mol) of Y(NO3)3•5H2O (Merck, 0.1181 and 0.2362 g, respectively, (0.0005 and 0.001 mol) of Ca(NO3)2•4H2O (Merck, >98.5%), 5.1086 g, (0.02 mol) of Ba(CH3COO)2 (Merck, >99%) and 7.9860 g, (0.04 mol) of Cu(CH3COO)2•H2O (Merck, >99%) were dissolved in a mixture of 200 cm3 ethanol and 200 cm3 water yielding clear blue solutions. 50 cm3 ethanediol and 30 g citric acid were then added to the solutions leading to the appearance of green collloidal precipitates. The precipitates were dissolved with 300 cm3 aq.NH3. During evaporation of the liquid under pressure (20 mbar) a blue gel was obtained... The gels obtained by the methods described were dried at 150 °C under reduced pressure at 5 mbar and then ground in an agate mill. The dried gel-powders were heated under oxygen at a rate of 1 K min-1 from room temperature to 500 °C, then at 2 K min-1 to 800 °C and kept at this temperature for 50 h yielding Y1-xCaxBa2Cu4Oy superconductors. The powders obtained were wet-milled for 4 h with 3 mm ZrO2-balls in n-propanol at 50 °C and 2 kPa. The dry powders were screened through a 32 µm sieve and pressed into pellets of 10 mm diameter at 1.2 GPa. The pellets were subsequently fired at 800 °C for 20 h under flowing oxygen at ambient pressure to obtain the respective superconductors."
Formula: Y1-xCaxBa2Cu4Oy
Informal Name: Y:124
Chemical Family: Y(Ca)-Ba-Cu-O
Chemical Class: Oxide
Structure Type: Polycrystalline
Manufacturer: In House
Commercial Name: In House
Production Date:
Lot Number:
Production Form:
Crystallography for Y:124; [Y(Ca)-Ba-Cu-O]
| Crystal System: | |
| Formula Units per Cell: | |
| Space Group: |
|
Cell Parameters
| x of Cax (formula unit) |
Temp
K
|
a
Å
|
b
Å
|
c
Å
|
| 0.00 |
296 |
3.839 |
3.864 |
27.222 |
| 0.05 |
296 |
3.839 |
3.864 |
27.238 |
| 0.10 |
296 |
3.839 |
3.864 |
27.241 |
Measurement Method: X-ray diffraction
"X-ray diffraction spectra were performed on a Geigerflex D-max II a (Rigaku, Japan) employing Ni-filtered CuKα radiation. The instrument was calibrated with Si... The lattice parameters were calculated by the least-square method."
Cautions: Evaluated Data
Critical Temperature for Y:124; [Y(Ca)-Ba-Cu-O]
| x of Cax (formula unit) |
Critical Temperature (K) |
| 0.0 |
80 |
| 0.05 |
82 |
| 0.10 |
85 |
Measurement Method: Four-probe method
"Resistivity and critical current density measurements were performed on 0.3 mm x 2 mm x 10 mm samples using the four-probe technique. Contacts were made by silver wires (0.4 mm diameter) attached to the samples by silver paint. A current of 10 mA was used for measuring the transition temperature."
The authors indicate that the critical temperature was evaluated as the zero resistance temperature.
Cautions: Evaluated Data
Critical Current Density for Y:124; [Y(Ca)-Ba-Cu-O]
| Temperature (K) |
x of Cax (formula units) |
Critical Current Density (kA/cm2) |
| 77 |
0.0 |
0.099 |
| 77 |
0.05 |
0.101 |
| 77 |
0.10 |
0.105 |
Measurement Method: Four-probe method
"Resistivity and critical current density measurements were performed on 0.3 mm x 2 mm x 10 mm samples using the four-probe technique. Contacts were made by silver wires (0.4 mm diameter) attached to the samples by silver paint. A current of 10 mA was used for measuring the transition temperature."
The authors indicate that the critical temperature was evaluated as the zero resistance temperature.
Cautions: Evaluated Data
