Material Specification for Nd:21; [Nd(Ce)-Cu-O]
Process: Solid State Reaction
Notes: "A specimen... was synthesized via a nitrate precursor, using as primary starting materials Nd2O3 (99.9%), (NH4)2[Ce(NO3)6] (99%), and CuO (98%). The solid nitrate mix obtained by stirred evaporation was dehydrated at 240 °C for 2 h, then decomposed and reacted by heating at 950 °C for 34 h, then at 1000 °C and 1050 °C for 14 h with intermediate regrindings. This was followed by pressing and then sintering in air at 1100 °C for 14 h. Superconductivity was induced by annealing the specimen in a nitrogen stream... for 18 h at 900 °C, and then for a further 6 h at 920 °C. Thermogravimetric measurements showed that the change from semiconducting to superconducting behavior was associated with a loss of approximately 0.02 oxygen atom per formula unit."
Formula: Nd1.85Ce0.15CuO4-x
Informal Name: Nd:21
Chemical Family: Nd(Ce)-Cu-O
Chemical Class: Oxide
Structure Type: Polycrystalline
Manufacturer: In House
Commercial Name: In House
Production Date:
Lot Number:
Production Form:
Density (mass) for Nd:21; [Nd(Ce)-Cu-O]
Measurement Method: Unknown density method
"The... polycrystalline... disk had a density of 6.21 g/cm
3, which is 85% of the crystal density."
Cautions: Unevaluated Data
No measurement details were noted.
Resistance (normal state) for Nd:21; [Nd(Ce)-Cu-O]
| x of O4-x (formula units) |
Temperature (K) |
Resistance (normal state) (mΩ) |
| 0.02 |
16 |
0 |
| 0.02 |
19 |
12 |
| 0.02 |
20 |
39 |
| 0.02 |
21 |
65 |
| 0.02 |
24 |
116 |
| 0.02 |
24 |
160 |
| 0.02 |
28 |
159 |
| 0.02 |
49 |
146 |
| 0.02 |
80 |
131 |
| 0.02 |
110 |
121 |
| 0 |
3 |
25400 |
| 0 |
6 |
22400 |
| 0 |
8 |
19800 |
| 0 |
22 |
14800 |
| 0 |
41 |
11100 |
| 0 |
66 |
8500 |
| 0 |
86 |
7100 |
| 0 |
103 |
5800 |
| 0 |
118 |
5200 |
Measurement Method: Four-probe method
"The resistance was measured using a standard four-probe dc technique in a variable temperature cryostat." No additional measurement details were noted.
Cautions: Evaluated Data
Digitized data were obtained fromn Figure 1 of the paper.
Specific Heat for Nd:21; [Nd(Ce)-Cu-O]
| x of O4-x (formula units) |
Temperature (K) |
Specific Heat (J kg-1 K-1) |
| 0 |
0.7 |
7.50 |
| 0 |
0.8 |
9.00 |
| 0 |
0.9 |
10.00 |
| 0 |
1.0 |
10.70 |
| 0 |
1.6 |
10.47 |
| 0 |
2.5 |
8.50 |
| 0 |
3.3 |
6.23 |
| 0 |
4.7 |
4.00 |
| 0 |
6.6 |
2.31 |
| 0 |
8.6 |
1.61 |
| 0 |
11.2 |
1.62 |
| 0 |
14.2 |
2.42 |
| 0 |
16.2 |
3.68 |
| 0 |
18.3 |
5.58 |
| 0 |
19.5 |
6.85 |
| 0.02 |
0.9 |
8.68 |
| 0.02 |
1.0 |
9.70 |
| 0.02 |
1.2 |
10.00 |
| 0.02 |
1.8 |
9.15 |
| 0.02 |
2.4 |
7.97 |
| 0.02 |
3.1 |
5.94 |
| 0.02 |
4.1 |
3.99 |
| 0.02 |
5.4 |
2.50 |
| 0.02 |
7.3 |
1.64 |
| 0.02 |
9.4 |
1.41 |
| 0.02 |
11.3 |
1.49 |
| 0.02 |
13.7 |
2.11 |
| 0.02 |
15.8 |
3.28 |
| 0.02 |
17.8 |
5.24 |
| 0.02 |
19.7 |
7.43 |
Measurement Method: Heat-pulse calorimeter
The authors cite S.J. Collocott, Aust. J. Phys., Vol. 36, 573 (1983), and summarize the procedure as follows. "The specific heat... was measured using a
3He-
4He semiadiabatic heat-pulse calorimeter."
Cautions: Evaluated Data
Digitized data were obtained from Figure 4 of the paper.
Debye Temperature for Nd:21; [Nd(Ce)-Cu-O]
| x of O4-x (formula units) |
Debye Temperature (K) |
| 0.02 |
409 |
| 0.0 |
445 |
Measurement Method: Debye calculation
"... the limiting value for the temperature (was) calculated from (a model relation)."
Cautions: Evaluated Data
"(There were) problems in determining an accurate value for a, and hence (the Debye temperature), as the fitting parameters a and b are accounting for the lattice in the presence of the large background."
