Phy (Φ) -COSMOS
History
The Phy-CoSMOs laboratory stands for Phase Control in Smart Materials Operations. Working closely with Janis Research Industry, we designed and developed a prototype set of cryostats and magnets with inter-changeable cryostats and probes.
We received our two magnets (“Gonzales” and “John“), top loading VTI and dilution fridge (with a top loading option) in 2011. The 9T/4T vector magnet and VTI reached our lab and were commissioned in early 2011 whereas the 16T magnet and dilution fridge were delivered and commissioned later in November that year.
Equipment and Capabilities
VTI – temperature range: 300K to 1.7K.
Dilution Fridge – temperature range: down to 7 mK when using pure silver cold finger, with option to use either pure silver or gold coated copper top loaders.
16T Magnet – single axis magnet
9T/4T Magnet – a vector magnet with 9T along the z-axis and 4T along the x-axis with a maximum vector sum of 3.5T along the diagonals.
Both the VTI and the Dilution Fridge can be used individually as standalone (for cryogenic experiments in zero magnetic field) or mounted within either of the magnet bores. The magnets can also accommodate other in-house designed and custom made cryostats and probes.
Our recovery lines re-collects any helium boiled off from our magnets and cryostats. The helium is then purified in a liquid nitrogen trap and condensed in a Cryomech reliquifier at a rate of 22 L/day.
Our “dry” dilution fridge operates with either a pure silver cold finger or three independent and interchangeable top loaders: two made of gold coated copper, and one made of pure silver.
The dry system operates on a closed loop 3He – 4He mixture complete with its own compressor and reliquifier. Interchangeability of the probes ensures a minimum downtime in between experiments.
Phy-COSMOS is designed to accommodate a range of experimental methods. The probes come with a 2” sample space, a range of coaxial cables, superconducting wires and semi-rigid cables on selected probes. Experiments can be carried out in UHV as well, allowing for a better isolation of the samples from surroundings for precise environment control when necessary.
Our Team has already built a set of electric, thermal and magnetic methods for experiments in the above mentioned cryostats and magnets. These include – to name few – heat capacity, electric and thermal magnetotransport, dielectric spectroscopy and electrical polarization.
The animation below describes the versatility of our cryogenic systems and illustrates the ability of both the VTI as well as the Dilution Fridge to be mounted onto either magnets: the 9T and 4T dual axis magnet and the 16T magnet. In the final scene, we see both the VTI and Dilution Fridge being used individually, while a separate custom made probe is inserted into the 16 T magnet.
This configuration, whereby the fridges are separate entities from the magnets, therefore allows us to have a slew of different options such as:
(i) VTI with 16 T magnet
(ii) VTI with 9T and 4T dual axis magnet
(iii) Dilution fridge with 16T magnet
(iv) Dilution fridge with 9T and 4T dual axis magnet
(v) VTI and Dilution Fridge as stand alone, with both magnets available for other custom made probes
In order for this system to be feasible, much care has been taken to ensure that the field centre of both magnets are located at the exact sample position for both the VTI and Dilution Fridge when properly mounted.
