Material Specification for Gd:123; [Gd-Ba-Sr-Cu-O]
Process: Solid State Reaction
Notes: "Samples... were prepared by mixing and grinding stoichiometric quantities of Gd(NO3)36H20 (purity >99.9%), BaCO3 (>99.9%), SrCO3 (>99.9%) and CuO (>99.99%). The mixture was pressed into pellets, calcined in air at 940 °C for 24 h, and furnace cooled to room temperature. The calcined pellets were grinded in an automatic mill for about one hour, and the powders were pressed into pellets of 13 mm diameter at 800 MPa. The second calcination, carried out under flowing oxygen, was performed at 940 °C for 24 h. Subsequently, the samples were cooled to 600 °C. Further cooling to room temperature, still under flowing oxygen, was accomplished at a rate of 60 °C per hour... To change the oxygen concentration, these samples were subjected to two different thermal treatments: (a) Samples were heated in air to 940 °C for two hours and quenched to room temperature by removing the sample from the furnace. (b) Samples (a) were reheated to 650 °C for two hours and subsequently cooled to room temperature at a rate of 80 °C/h. This treatment was performed under flowing argon (purity >99.995%)."
Formula: GdBaSrCu3O7-x
Informal Name: Gd:123
Chemical Family: Gd-Ba-Sr-Cu-O
Chemical Class: Oxide
Structure Type: Polycrystalline
Manufacturer: In House
Commercial Name: In House
Production Date:
Lot Number:
Production Form:
Crystallography for Gd:123; [Gd-Ba-Sr-Cu-O]
| Crystal System: | |
| Formula Units per Cell: | |
| Space Group: |
|
Cell Parameters
| x of O7-x (formula units) |
Temp
K
|
a
Å
|
b
Å
|
c
Å
|
| 0.0 |
300 |
3.835(1) |
-- |
11.554(2) |
| 0.4 |
300 |
3.827(1) |
3.849(1) |
11.574(4) |
| 0.6 |
300 |
3.855(1) |
-- |
11.581(3) |
Measurement Method: X-ray diffraction
"X-ray diffraction (XRD) of the powder was carried out at room temperature by using CuKα radiation. The instrument was calibrated with silicon powder. The XRD intensity was measured from 6° to 100° (2θ) at a speed of 0.25°/min."
Cautions: Evaluated Data
Critical Temperature for Gd:123; [Gd-Ba-Sr-Cu-O]
| x of O7-x (formula units) |
Critical Temperature (K) |
| 0.0 |
86 |
| 0.4 |
24 |
Measurement Method: Four-probe method
"The temperature dependence of the electrical resistance down to 20 K was measured by employing a standard DC four-point probe technique. The currents used for the measurements were around 4 mA to 10 mA." No additional measurement details were noted.
Cautions: Evaluated Data
Resistivity (normal state) for Gd:123; [Gd-Ba-Sr-Cu-O]
| T (K) |
Resistivity (normal state) (mΩ·cm) |
| 300 |
1.2 |
| 300 |
3.4 |
| 300 |
178 |
Measurement Method: Four-probe method
"The temperature dependence of the electrical resistance down to 20 K was measured by employing a standard DC four-point probe technique. The currents used for the measurements were around 4 mA to 10 mA." No additional measurement details were noted.
Cautions: Evaluated Data
