Material Specification for ; [Y-Ni-B-C]
Process: Melt Processed
Notes: "Superconducting YNi2B2C samples were prepared by direct synthesis from the elements in a semilevitation high-frequency induction furnace under pure argon atmosphere on a water-cooled tantalum hearth. The starting materials were Y, 99.9 wt.% purity (from Koch-Light Lab.), Ni, 99.99 wt.% purity, B, 99.7 wt.% purity (from Aldrich Chem.) and C, 99.995 wt.% spectrotech purity (from Johnson Matthey). The samples in the form of buttons were turned and remelted four times to ensure homogenization and then slowly cooled down to room temperature. Micrographic examination and microanalysis (EDAX) showed the presence of almost single-phase YNi2B2C in the form of close aggregates of plate-like crystals and a few percent of the very stable borocarbide YB2C2."
Formula: YNi2B2C
Informal Name:
Chemical Family: Y-Ni-B-C
Chemical Class: Carbide
Structure Type: Polycrystalline
Manufacturer: In House
Commercial Name: In House
Production Date:
Lot Number:
Production Form:
Crystallography for ; [Y-Ni-B-C]
| Crystal System: | |
| Formula Units per Cell: | |
| Space Group: |
|
Cell Parameters
|
Temp
K
|
a
Å
|
b
Å
|
c
Å
|
| 296 |
3.528 |
-- |
10.546 |
Measurement Method: X-ray diffraction
"X-ray analysis, carried out by a Guinier-Stoe camera with a silicon internal standard, confirmed YNi
2B
2C as a variant of the tetragonal ThCr
2Si
2 type structure with additional C in the Y plane..." No additional measurement details were noted.
Cautions: Unevaluated Data
Critical Temperature for ; [Y-Ni-B-C]
| Tc(onset) (K) |
Critical Temperature (K) |
| 14 |
13 |
Measurement Method: Four-probe resistance
"Resistance versus temperature measurements were performed on our samples by a simple four-probe technique. The samples were accurately shaped in the form of a long bar for the determination of the absolute value of the resistivity...yielding...resistivity (T = 300 K) = 125 ± 5 µΩ cm." No additional measurement details were noted.
Cautions: Unevaluated Data
Resistivity (normal state) for ; [Y-Ni-B-C]
| Temperature (K) |
Resistivity (normal state) (mΩ·cm) |
| 13.3 |
0.000 |
| 13.9 |
0.012 |
| 14.1 |
0.027 |
| 17.7 |
0.028 |
| 25.0 |
0.029 |
| 38.6 |
0.032 |
| 50.5 |
0.037 |
| 75.1 |
0.048 |
| 87.1 |
0.054 |
| 99.0 |
0.059 |
Measurement Method: Four-probe resistance
"Resistance versus temperature measurements were performed on our samples by a simple four-probe technique. The samples were accurately shaped in the form of a long bar for the determination of the absolute value of the resistivity...yielding...resistivity (T = 300 K) = 125 ± 5 µΩ cm." No additional measurement details were noted.
Cautions: Unevaluated Data
Digitized data were obtained from Figure 1 of the paper.
Energy Gap(2 delta) for ; [Y-Ni-B-C]
| 2Δ/kTc () |
Energy Gap (2Δ) (meV) |
| 3.8 ± 0.4 |
4.4 ± 0.4 |
Measurement Method: Scanning tunneling microscopy
"Tunneling measurements were performed by a low-temperature scanning tunneling microscope (STM). The STM unit built in our Laboratory consists of two front-faced disk piezo-scanners for sample motion towards the tip and for x-y tip displacement, respectively. The scanning head, suspended by Cu/Be coil springs to reduce the influence of external vibrations, is realized in titanium to ensure rigidity and can be directly immersed in liquid helium. Standard low-noise electronics is used to drive the unit. The tunneling current is stabilized by a feedback loop and an analogic memory is used in order to deactivate the feedback during the measurement of the I-V characteristic. This is taken with a voltage signal frequency of 0.1-1 Hz and averaging over 50-100 measurements to improve the signal-to-noise ratio. Measurements at different points of the sample surface were performed by mechanically and chemically sharpened Au or Nb tips."
Cautions: Evaluated Data
Debye Temperature for ; [Y-Ni-B-C]
| Debye Temperature (K) |
| 310 ± 20 |
Measurement Method: Four-probe resistance
"Resistance versus temperature measurements were performed on our samples by a simple four-probe technique. The samples were accurately shaped in the form of a long bar for the determination of the absolute value of the resistivity...yielding...resistivity (T = 300 K) = 125 ± 5 µΩ cm." No additional measurement details were noted.
Cautions: Unevaluated Data
