POLAR Bath Cryostat UHV SPM
STM, qPlus®-AFM & Spectroscopy
Integrated TRIBUS Head
Excellent SPM Stability
Minimum Temperature: TMIN<5K
Helium Holding Time: > 200h
Vertical Magnetic Field: B z = ±5T
The POLAR SPM
The new SIGMA POLAR UHV SPM is a low-temperature Scanning Probe Microscope (SPM) for highest resolution STM,qPlus®-AFM, and spectroscopy experiments in a temperature range of between <5K and 300K and in high magnetic fields of up to 5T.
To date, the twin requirements of long hold time and high mechanical stiffness desired in an optimised Low-Temperature SPM cryostat have been conflicting requirements. For this reason conventional SPM cryostats are a compromise between being mechanically stable for good SPM performance or have a reasonable hold time. POLAR solves these compromises with our new unique proprietary cryostat concept.
The ultra-compact design of the cryostat with a height of <60cm ensures an immense mechanical stiffness and thus in an excellent STM stability. The hold time is optimised through a series of thermal decoupling stages and thermal radiation shields, designed to deliver an extremely low helium consumption. With a liquid helium (LHe) consumption of less than 1 litre per 24 hours, the instrument achieves a hold time of >200 hours at <5K before the cryostat needs to be refilled.Alternatively, the SPM can be operated with liquid nitrogen (T <79K). Viewports and closable entry doors in the radiation shields allow for SPM in-situ tip/sample exchange, optical access or in-situ evaporation.
The low helium consumption offers both an economic benefit and permits long term measurement sessions.
The heart of the multi-application POLAR SPM is the TRIBUS SPM head. It is integrated into a compact bath cryostat system and employs a spring suspension and eddy current damping system for optimum mechanical decoupling. The TRIBUS SPM has a 3D (X/Y/Z) motor for tip and sample navigation, is extremely mechanically stable and offers numerous access ports for optical observation, in-situ sample and probe exchange and evaporation onto the sample/substrate. An effective thermal shielding in combination with the compact design and short mechanical loops, and a high symmetry within the STM head are responsible for a very low relative drift between sample and measurement probe. Up to 10 additional electrical contacts to the sample extend the range of possible measurement modes.
The proven flag style sample plate design ensures the compatibility with existing SPM instrumentation and transfer systems. As an option, a superconducting coil for vertical fields of ±5T can be offered for the POLAR SPM.
The UHV compatible dry magnet is mounted at the bottom of the helium cryostat.
In combination with tip/sample preparation (heating, ion etching, evaporation…) the POLAR facilitates a wide range of SPM operation modes including STM, qPlus-AFM, Spin Polarized Tunneling as well as related spectroscopy (STS, I/V, dI/dV, df(V),force spectroscopy, IETS, …) experiments.