Cutting-edge
Systems
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Scanning Probe Microscopy goes Dry mK
atomic/magnetic force and scanning gate microscopy in dry dilution refrigerators
Since 2001, attocube has been pioneering cryogenic scanning probe
microscopy, and hence substantial experience has also been gained in
mK environments with our instruments. Even when it comes to dry systems,
which pose a particular challenge to sensitive techniques due to
the vibrations induced by the cold head, we have achieved outstanding
results both in terms of base temperature (despite the additional thermal heat
load due to scanning) and noise specifications. Our instruments
are based on state-of-the-art dry dilution refrigerators with a cooling
power of several hundred μWatts at 100 mK, fully automated gas
handling systems and wiring that is perfectly matched to both the
operation of the microscope as well as to the additional requirements
of the customer.
Long Term Measurement at mK Temperatures
This scan above nicely demonstrates the stability of a complete system, an
attoAFM I together with a LD400 cryo-cooler from BluFors Cryogenics. For this
25 x 25 μm² (800 x 800 pixel) scan, which took about 12 hrs, the pulse-tube
cooler was enabled the whole time. The temperature was stable at ~40 mK
measured at the mixing chamber – it was slightly higher due to the higher scan
speed of close to 1 μm/s.
5 µm
(attocube applications in collaboration with BluFors Cryogenics, 2014)
Atomic Force Microscopy at 80 mK
1 µm
This AFM-topography test-measurement of an 20 nm high calibration grating
was performed in a pulse-tube based dilution fridge from Leiden Cryogenics.
Even though the sample was scanned with 3 μm/s, the temperature did not
rise above 80 mK, while the base temperature of the (not yet optimized) braid
cooled sample was at around 62 mK. Geophone measurements verified the low
vibrations of the platform and showed that it is a suitable approach for high
resolution, ultra-low temperature AFM-type experiments. attocube now also
offers sensitive applications like scanning gate microscopy in dry dilution refrigerators. Contact us for more information.
(attocube applications in collaboration with Leiden Cryogenics, 2011)
1 µm