Physical Property Measurements in a cryogen-free system (PPMS DynaCool)
PPMS DynaCool from Quantum Design
The PPMS DynaCool is a completely redesigned instrument that provides all the capabilities of the Physical Property Measurement System without the need for any liquid cryogen. The system uses a single, two-stage pulse tube cryocooler for both the superconducting magnet and the temperature control system, providing an efficient, low vibration environment for sample measurements that simultaneously provides lower maintenance costs.
Measurements of material properties like specific heat, magnetic AC and DC susceptibility and both electrical and thermal transport properties (like Hall effect, thermoelectric figure of merit and Seebeck effect) can be done at down to 1.9 K and at up to 14 T.
|Truly cryogen-free - no need for liquid cryogen|
|Temperature range of 1.9 K – 400 K|
|9 T and 14 T magnets available|
|Continuous low-temperature control – maintains temperatures below 4.2 K for indefinite period of time and offers smooth temperature changes when warming and cooling through 4.2 K|
|Fully automated operation of PPMS DynaCool measurement options|
A novel gas flow regulation system improves both cooling power and temperature stability as compared to the already state-of-the-art PPMS temperature control Quantum Design customers have come to expect. With this new control system the PPMS DynaCool is capable of cooling a standard PPMS sample puck from 300 K to a stable 1.9 K, in less than 40 minutes. The so-called continuous low-temperature control (CLTC) maintains temperatures below 4.2 K for indefinite periods of time and offers smooth temperature transitions when warming and cooling down to 4.2 K.
The PPMS DynaCool comes equipped with either a 9 T or 14 T conduction-cooled superconducting switch-less magnet system. The PPMS DynaCool-9T now includes an integrated magnetic shield capable of maintaining the five gauss line very near to the surface of the cryostat cabinet allowing these systems to be installed closer to other sensitive instruments for better lab space utilization.
The PPMS DynaCool comes with an integrated cryopump and vacuum gauge for controlling the sample environment.
The flexibility of the PPMS DynaCool allows you to create your own experiments and easily interface them to the sample chamber using inserts such as the multi-function probe which provides a fully customizable sample interface. Meanwhile, the cryostat functions such that the temperature and magnetic field can be controlled from external programs like LabVIEW or other third party software. The integrated helium re-liquefier uses a very low amount of liquid helium for temperature control. This makes the system virtually cryogen-free. Helium gas is only needed for purging the sample chamber.
Vibrating sample magnetometer VSM
The vibrating sample magnetometer (VSM) is a powerful measurement system to be used for magnetic sample characterization. The VSM option transforms your PPMS into a sensitive DC magnetometer for fast data acquisition. The movement of the sample is done by a special sample transport, which has a linear characteristic and thus is very precise and flexible. Further options extend the capability of the VSM:
- Rapid and completely automated centering operation of the sample
- Sensitive DC magnetic moment measurement up to the maximum field of the magnet
- VSM measurement system is based on the CAN network protocol and includes the model 1000 CAN tower
- Sweeping of the magnetic field or of the temperature
AC susceptibility option ACMSII
The AC measurement system (ACMS) provides you with the capability to perform both AC susceptibility and extraction DC magnetization measurements:
- For measurement of AC susceptibility and DC magnetization.
- Direct phase nulling technique measures and cancels background AC shifts at every measurement.
The Quantum Design heat capacity option measures the heat capacity at constant pressure Cp.
This option controls the heat added to and removed from a sample while monitoring the resulting change in temperature. During a measurement, a known amount of heat is applied at constant power for a fixed time, and then this heating period is followed by a cooling period of the same time. This option uses a relaxation technique that combines the best measurement accuracy with robust analysis techniques.
Electro-transport option (ETO)
The electrical transport option enables users to make several different types of transport measurements over a wide range of resistance values and sample types. The option contains two separate channels each with their own dedicated electronics to allow simultaneous, continuous resistance measurement of two different samples. Each channel’s electronics consists of a precision current source and voltage preamplifier coupled to a digital signal processor (DSP).
- Resistance in 2- or 4-wire mode
- The classic 4-wire mode has two leads for the current and two leads for the potential drop
- Current-voltage curves
- Differential resistance curves
„We use the DynaCool system both for electronic measurements (ETO- option) as well as for magnetrometric measurements (VSM-option). The system is used 24/7. A key feature for us is the easy handling of the system even at low temperatures (up to 1,8 K) and magnetic fields up to ±9 Tesla. The system is used not only by established scientists, but also by students, who have no experience of cryotechnology or superconducting magnets. Due to the easy handling the students can completely concentrate on the scientific problems and do rarely get held up by issues regarding the instrument.”
- Dr. D. Görlitz, Universität Hamburg