Material Specification for Y:124; [Y(Pr)-Ba-Cu-O]
Process: Sol-Gel
Notes: "The percursors were synthesized using a sol-gel technique. Stoichiometric amounts of Y2O3, Pr6O11, Ba(NO3)2 and CuO of >99.9% purity, their correct molar proportions being determined by gravimetric methods, were dissolved in dilute nitric acid by heating and stirring the solution. Citric acid and ethyleneglycol were added in the proportions of one mole and 30 moles, respectively, for each mole of metal cation. The solutions were treated at 110 °C to remove most of the water from the solutions. As the solutions became concentrated, a brown colloid was formed. After completion of this reaction the temperature of the solutions was rapidly increased to 190 °C and kept at this temperature. As the excess of ethyleneglycol evaporated a gel formed which was subsequently decomposed to a fine powder by stirring on a hot plate at 300 °C. The percursors were pyrolyzed and treated at 830 °C for 24 h in an atmosphere of flowing oxygen, forming a mixture of Y(Pr)-123 and CuO. The powders were then sintered as pellets at 830±5 °C for four days with several intermediate grindings. After this treatment Y(Pr)-124 was the main phase. In order to complete the reaction, it was necessary to continue this treatment for several days more."
Formula: Y1-xPrxBa2Cu4O8
Informal Name: Y:124
Chemical Family: Y(Pr)-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(Pr)-Ba-Cu-O]
| Crystal System: | Orthorhombic |
| Formula Units per Cell: | 2 |
| Space Group: |
Ammm
|
Cell Parameters
| x of Prx (formula units) |
Temp
K
|
a
Å
|
b
Å
|
c
Å
|
| 0.0 |
296 |
3.8448(2) |
3.8682(2) |
27.242(1) |
| 0.4 |
296 |
3.8614(2) |
3.8807(2) |
27.260(2) |
| 0.8 |
296 |
3.8797(2) |
3.8919(2) |
27.296(1) |
Atomic Coordinates
| x of Prx (formula units) |
Atom |
Temp
K
|
a-axis |
b-axis |
c-axis |
| 0.0 |
Y/Pr |
296 |
0.5 |
0.5 |
0 |
| 0.0 |
Ba |
296 |
0.5 |
0.5 |
0.1349(2) |
| 0.0 |
Cu(1) |
296 |
0 |
0 |
0.2127(1) |
| 0.0 |
O(1) |
296 |
0 |
0 |
0.1457(2) |
| 0.0 |
O(2) |
296 |
0.5 |
0 |
0.0532(2) |
| 0.0 |
O(3) |
296 |
0 |
0.5 |
0.0522(2) |
| 0.0 |
O(4) |
296 |
0 |
0.5 |
0.2172(2) |
| 0.4 |
Y/Pr |
296 |
0.5 |
0.5 |
0 |
| 0.4 |
Ba |
296 |
0.5 |
0.5 |
0.1354(2) |
| 0.4 |
Cu(1) |
296 |
0 |
0 |
0.2132(1) |
| 0.4 |
O(1) |
296 |
0 |
0 |
0.1455(2) |
| 0.4 |
O(2) |
296 |
0.5 |
0 |
0.0545(1) |
| 0.4 |
O(3) |
296 |
0 |
0.5 |
0.0537(2) |
| 0.4 |
O(4) |
296 |
0 |
0.5 |
0.2176(2) |
| 0.8 |
Y/Pr |
296 |
0.5 |
0.5 |
0 |
| 0.8 |
Ba |
296 |
0.5 |
0.5 |
0.1365(2) |
| 0.8 |
Cu(1) |
296 |
0 |
0 |
0.2134(1) |
| 0.8 |
O(1) |
296 |
0 |
0 |
0.1457(2) |
| 0.8 |
O(2) |
296 |
0.5 |
0 |
0.0562(1) |
| 0.8 |
O(3) |
296 |
0 |
0.5 |
0.0550(2) |
| 0.8 |
O(4) |
296 |
0 |
0.5 |
0.2173(1) |
Measurement Method: Neutron diffraction
"Time-of-flight neutron diffraction data were collected at room temperature for three of the samples at the spallation source ISIS, RAL, using the high flux, medium resolution powder diffractometer, POLARIS. The ten
3He gas detectors are placed at 130-158° in 2θ and cover a d-range of 0.2 σ < d < 3.2 σ with a resolution of about 5 x 10
-3 σ. A total of 4576 observations were collected and the refinement included 562 reflections in the range 0.65
Cautions: Evaluated Data
Critical Temperature for Y:124; [Y(Pr)-Ba-Cu-O]
| x of Prx (formula units) |
Critical Temperature (K) |
| 0.00 |
82 |
| 0.05 |
80 |
| 0.075 |
79 |
| 0.10 |
79 |
| 0.20 |
75 |
| 0.40 |
64 |
| 0.60 |
45 |
| 0.80 |
6 |
Measurement Method: Four-probe method
"The superconducting transition (T
c onset) was measured by the usual four probe resistivity technique... The transition widths were between 5 and 20K (10%-90%), increasing with Pr content." No additional measurement details were noted.
Cautions: Evaluated Data
Digitized data were obtained from Figure 3 of the paper.
