Material Specification for Y:124; [Y-Ba-Cu-O]
Process: Oxalate Precipitation
Notes: The authors cite J.S. Ho et al., Appl. Phys. Lett., Vol. 58, 2426 (1990), and summarize the procedure as follows. "... high purity Y(NO3)3•nH2O (n=4-6), Ba(NO3)2 and Cu(NO3)2•6H2O powders (Merck AG) with a cationic molar ratio of Y:Ba:Cu=1:2:4 (using 0.005 mol of Y^(3+)) were dissolved in distilled/deionized water. An aqueous solution of oxalic acid (as a precipitant) and triethylamine (as a base) was prepared by mixing 0.025 mol of oxalic acid and 25 mL of triethylamine in 10 mL of water. The solution of the metal nitrate salts was then added dropwise into the oxalic acid/triethylamine solution with vigorous stirring. During the mixing, a pale blue coprecipitate rapidly formed. The solution was then cooled, with stirring in an ice-water bath. The coprecipitate was subsequently dried at 120 °C in air for 10 h and then calcined at 700 °C in air for 10 h to eliminate any organic components. The resulting fine black powder was pressed into a pellet and sintered at 805 °C in flowing oxygen for periods of 2-4 days and quenched in air."
Formula: YBa2Cu4O8
Informal Name: Y:124
Chemical Family: Y-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-Ba-Cu-O]
| Crystal System: | Orthorhombic |
| Formula Units per Cell: | |
| Space Group: |
|
Cell Parameters
|
Temp
K
|
a
Å
|
b
Å
|
c
Å
|
| 296 |
3.84 |
3.87 |
27.2 |
Measurement Method: X-ray diffraction
Cautions: Unevaluated Data
No measurement details were noted.
Critical Temperature for Y:124; [Y-Ba-Cu-O]
| Critical Temperature (K) |
| 83 |
Measurement Method: SQUID magnetometer
Cautions: Unevaluated Data
No measurement details were noted.
Critical Flux Density Hc2 for Y:124; [Y-Ba-Cu-O]
| Temperature (K) |
Crit.Mag.Flux Density Hc2 (T) |
| 78.2 |
5.8 |
| 80.0 |
4.0 |
| 80.9 |
2.0 |
| 81.8 |
0.5 |
| 82.6 |
0.1 |
Measurement Method: Vibrating sample magnetometer
"The upper critical field and magnetic irreversibility line were determined through dc magnetization measurements carried out in a vibrating sample magnetometer (VSM3001 Oxford Instruments)... The H
(T) was defined as the onset of diamagnetism and was determined in practice from the zero intercept of the extrapolated linear magnetization below Tc... The irreversible field, H
(T), is defined as the onset of detectable irreversibility in the isothermal dc magnetization."
Cautions: Evaluated Data
Digitized data were obtained from Figure 5 of the paper.
Thermoelectric Power for Y:124; [Y-Ba-Cu-O]
| Temperature (K) |
Thermoelectric Power (µV/K) |
| 84 |
4.5 |
| 86 |
4.8 |
| 94 |
4.9 |
| 110 |
4.8 |
| 138 |
4.4 |
| 158 |
4.4 |
| 192 |
5.0 |
| 220 |
5.6 |
| 254 |
6.3 |
| 285 |
6.9 |
Measurement Method: Thermopower measurement
"Measurements of thermoelectric power (TEP) were made by a steady state technique, employing a small reversible temperature gradient of between 0.4-1 K. The data have been corrected for the contribution of the gold measurement leads."
Cautions: Evaluated Data
Digitized data were obtained from Figure 3 of the paper.
Irreversibility Field for Y:124; [Y-Ba-Cu-O]
| Temperature (K) |
Irreversibility Field (T) |
| 36 |
13.3 |
| 40 |
9.9 |
| 50 |
4.9 |
| 60 |
2.7 |
| 70 |
1.0 |
| 75 |
0.6 |
| 83 |
0.1 |
Measurement Method: Vibrating sample magnetometer
"The upper critical field and magnetic irreversibility line were determined through dc magnetization measurements carried out in a vibrating sample magnetometer (VSM3001 Oxford Instruments)... The H
(T) was defined as the onset of diamagnetism and was determined in practice from the zero intercept of the extrapolated linear magnetization below Tc... The irreversible field, H
(T), is defined as the onset of detectable irreversibility in the isothermal dc magnetization."
Cautions: Evaluated Data
Digitized data were obtained from Figure 5 of the paper.
