Oxford Instruments has installed a Cryofree dilution refrigerator and other instrumentation at Salamanca University in Spain for use in graphene studies.
Dr Enrique Diez from Salamanca University works on the subject of graphene, and the instrument will enable continuous measurements from 10mK up to 40K from one cryostat and without the need for liquid cryogen.
Diez was working at Princeton University in the US when he was offered a position at Salamanca University to establish a laboratory to study magneto-transport in nano-electronic devices.
He said: 'When I set up my laboratory, we came to the conclusion that technologies based on the use of liquid helium were no longer sustainable.
'We looked at new environmental-friendly technologies, which could provide ultra-low temperature and high-magnetic-field environments, without the need for liquid helium,' he added.
Diez has set up a flexible, cryogen-free suite of three inserts including a 4K cryostat, 300mK He-3 insert and a 10mK dilution refrigerator.
All inserts are interchangeable and can be fitted to a 12 T, 55mm standalone Cryofree magnet.
Diez said: 'This setup gives us complete flexibility in the type of experiments we need to perform.
'We are able to make measurements from millikelvin temperatures to room temperature continuously without having to change cryostats.
'Apart from the convenience, it also ensures accuracy of our results.
'We can also use the magnet cryostat as standalone for quantum hall measurements at room temperature.
'This is particularly useful as graphene exhibits quantum hall plateaus at room temperature,' he added.
Apart from the obvious reduction in operating costs and preservation of helium, a scarce natural resource, dry streams are also easy to operate at the touch of a button.
Diez has devoted the last two years to the study of magneto-transport properties of graphene.
He looked closely at the temperature dependence of the plateau-plateau and plateau-insulator transition in graphene.
He reported the first measurement of the scaling exponent for the plateau-insulator quantum phase transition in graphene.
Diez said: 'Our special 3He system was ideal for this type of measurements as we were able to cool down our samples to 280mK from room temperature in one shot, which was really important for the accuracy of our study.
'We are now planning to extend our studies on graphene to lower temperatures.
'Our new cryogen-free dilution refrigerator will enable continuous measurements from 10mK up to 40K,' he added.
