Insiders will probably think that electrical measurements in the PPMS/DynaCool are not at all new. And they do have a point, as electrical measurements have been around for a very long time as a standard option, and are one of the most popular options alongside magnetic measurements (VSM) at that. The entry-level variant is the "resistivity option" and spans a range from about 10 µΩ to about 5 MΩ and thus not only meets many requirements, but is also sometimes used to read out a thermometer. For more demanding measurements, Quantum Design offers the "ETO option". It is based on AC excitation (lock-in), and for two-point measurements enables resistances down to the lower gigaohm range to be determined.
A cooperation between Quantum Design and Lake Shore has now lead to the emergence of a third option for electrical measurements. With its M91 FastHall controller, Lake Shore offers a clever electronics optimized for Hall effect measurements, with the additional benefit that it can be easily adapted to fit into existing measurement setups. In contrast to the "Resistivity" and "ETO" measurement options, the M91 takes a different approach. It is not (not yet?) controlled via the PPMS/DynaCool software MultiVu, but via MeasureLink from Lake Shore. MeasureLink controls both the temperature and the magnetic field and performs the measurements. This means that you have to do without the convenience provided by MultiVu, but you gain flexibility, especially when measuring the Hall effect. This makes the M91 a great addition, not only to existing PPMS and DynaCool systems, but also as part of a new investment.
M91 FastHall Controller – Overview
- Resistance range: 10 mΩ to 10 MΩ, optionally up to 200 GΩ
- Hall mobility: 0.001 to 106 cm2/V s
- Voltage range (excitation): 10 mV to 10 V
- Resolution: up to 100 nV
- Current range (excitation):
- 1 µA to 100 mA (10 pA to 1 µA)Resolution: up to 10 pA
- Sample holder: Puck or special sample (currently in development)
PPMS/DynaCool – Overview
- Temperature range: 1.9 K to 400 K, optional down to 400 mK (He3) or 50 mK (DR)
- Installed magnet: 9 T, 12 T, 14 T or 16 T