Resistivity, Hall effect, magnetoresistance are measured in metals and superconductors in order to investigate the electronic structure (Shubnikov – de Haas oscillations, Hall effect), and the carrier mobility (magnetoresistance, resistivity).
In static field, low noise lock-in measurements are performed. Several samples can be fitted on a single probe, with or without rotation stage. Transport measurements are routinely performed in pulsed magnetic field in sample with resistance as low as 1 mohm. The measurements are performed with a current excitation between 0.1 mA and 10 mA at a frequency in the range 2 – 80 kHz. A high-speed acquisition system is used to digitize the reference signal (current) and the voltage drop across the sample. The data are post-analyzed with software to perform the phase comparison.
Above we show the magnetoresistance measured in an overdoped cuprate high-Tc superconductor, Tl2Ba2CuO6+delta. On top of a monotonic background, a small but clearly resolved oscillatory component appears in high field. Those Shubnikov – de Haas oscillations provide pivotal information about the electronic structure of those systems. Check here for more details on this study.
| Pulsed field | Static field | |
|---|---|---|
| Bmax | 90 T | 36 T |
| Temperature range | 0.5 K - 300 K | 0.05 K - 300 K |