Material Specification for Y:124; [Y-Ba-Cu-O]
Process: Solid State Reaction
Notes: The authors cite J. Niska et al., J. Mater. Sci. Lett., Vol. 9, 770 (1990), and summarize the procedure as follows. "Bulk material with a porosity < 2% was produced by hot isostatic pressing CuO with Y 1:2:3."
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:
Critical Temperature for Y:124; [Y-Ba-Cu-O]
| ΔTc (K) |
Critical Temperature (K) |
| 4 |
79 |
Measurement Method: Electrical resistance
Cautions: Unevaluated Data
No measurement details were noted. The resistive onset temperature was cited as T
c.
Thermal Conductivity for Y:124; [Y-Ba-Cu-O]
| Temperature (K) |
Thermal Conductivity (W m-1 K-1) |
| 30 |
5.5 |
| 39 |
8.8 |
| 49 |
10.8 |
| 59 |
10.9 |
| 101 |
10.0 |
| 157 |
8.8 |
| 192 |
8.4 |
| 243 |
7.6 |
| 273 |
7.3 |
| 300 |
7.3 |
Measurement Method: Thermal conduction methods
Thermal conductivity "... was measured on a 0.7 x 0.9 x 13.8 mm
3 rod, cut along the axis of the hot isostatic pressed cylinder... The thermal conductivity data were obtained over the range 30-310 K by two different methods. The longitudinal steady-state method was used in the range 30-160 K... In the range above 70 K we therefore measured instead the thermal diffusivity, a, using σngstrom's method... k was then calculated as k=adc
, where d is the density and c
the specific heat capacity... All measurements were carried out in a vacuum (less than 10-3 Pa = 10-5 mbar) and T was measured using type K thermocouples... The data are analyzed in terms of the relaxation time model."
Cautions: Evaluated Data
Digitized data were obtained from Figure 1 of the paper.
Debye Temperature for Y:124; [Y-Ba-Cu-O]
| Debye Temperature (K) |
| 170 ± 15 |
Measurement Method: Thermal conduction methods
Thermal conductivity "... was measured on a 0.7 x 0.9 x 13.8 mm
3 rod, cut along the axis of the hot isostatic pressed cylinder... The thermal conductivity data were obtained over the range 30-310 K by two different methods. The longitudinal steady-state method was used in the range 30-160 K... In the range above 70 K we therefore measured instead the thermal diffusivity, a, using σngstrom's method... k was then calculated as k=adc
, where d is the density and c
the specific heat capacity... All measurements were carried out in a vacuum (less than 10-3 Pa = 10-5 mbar) and T was measured using type K thermocouples... The data are analyzed in terms of the relaxation time model."
Cautions: Evaluated Data
"The fitted values of (the Debye temperature), 155-185 K, are significantly lower than the value found from c
(525 K), which, however, takes into account all lattice modes, including high-energy optical phonons. Since most of the heat is carried by acoustical phonons the effective (Debye temperature) for heat conduction should be lower than 525 K."
