| Local Contact |
William Knafo |
Cyril Proust / David Vignolles |
| Field range |
0 ... 90 T (100 T soon) |
0 ... 90 T (100 T soon) |
| Temperature range |
100 mK - 300 K (maximum field 60 T, ambient pressure)
1.4 K - 300 K (maximum field 90-100 T, ambient pressure) |
500 mK - 300 K (maximum field 90 T)
1.4 K - 300 K (maximum field 60 T or 70 T - rotating insert available) |
| Sample size |
to be adjusted to have appropriate resistance values (if metallic samples, room temperature resistance should be at least > 10-30 mOhm to have good high-field sensitivity at low temperature) |
Thickness of the sample need to be adjusted to get a resistance at least of the order of few mohms at low temperatures (see also sample holder) |
| Sensitivity |
lowest noise can be ≃ 0.04 mOhm (for a current of 10 mA) |
Typical noise for low resistance (< 1 ohm) measurements:
V = 0.1 µV @ zero field
V~1 µV @ maximum field
Good contact resistances (< 1ohm) are required to get this typical noise. |
| Measurement range |
|
Resistance ranging from mOhms to kOhms |
| Typical experiment |
4 contact resistivity or Hall effect (possibility to reverse the field direction) |
4 /6 contact measurements (possibility to reverse the field direction for Hall effect) |
| Sample Holder |
different sample holders, depending on the probe/magnet
Probes: - 4 mm diameter probe for > 90 T magnets
- 7 mm diameter probe for 70 T magnets (6 MJ)
- 20 mm diameter probe for long-duration 60 T magnet (4.5 MJ), probe used for pressure cell experiment or big samples |
2 (3) samples can be measured simultaneously up to 90 T (60 T)
Samples are usually mounted on sapphire platelet. Sample + platelet should fit in a diameter of 18 mm (60 T), 6 mm (70 T) and 4 mm (90 T) |
| Sample environment |
He4 cryostat, He3 inserts, dilution fridge (max field 60 T)
High Pressure up to 4 GPa (maximum field 60 T, lowest temperature 1.4 K) |
Gaseous helium from 300K down to 4.2 K, liquid helium or liquid ³He below |
| Examples |
60 T, 70 T, 80 T and 90 T magnets, He4 and dilution fridges (ambient pressure)
M.D. Watson et al., Phys. Rev. Lett. 115, 027006 (2015)
G.W. Scheerer et al., Phys. Rev. B 89, 165107 (2014)
High pressure combined with pulsed fields:
W. Knafo et al., Phys. Rev. B 95, 014411 (2017)
D. Braithwaite et al., Rev. Sci. Instrum. 87, 023907(2016). |
Quantum oscillations in an overdoped high-Tc superconductor
Nature 455, 952–955, 2008
Evidence for a small hole pocket in the Fermi surface of underdoped YBa2Cu3Oy
Nat. Commun. 6 6034 (2015)
Change of carrier density at the pseudogap critical point of a cuprate superconductor Nature 531 210 (2016) |
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