Acquisition of Helium Reliquefiers for Investigation of Novel Two-Dimensional Magnetoelectric Devices

The ability to perform experiments at low temperatures is critical to many areas of research in fundamental physics and materials science. In addition to enabling the investigation of the temperature-dependent behavior of materials, the ability to reach low temperatures allows the investigation of the intrinsic properties of materials and devices without the interference caused by thermal effects. This is particularly important for quantum information science, a topic of intense study worldwide, where very low temperatures are required in order to avoid decoherence of quantum wavefunctions. Almost universally, the preferred method to cool below 77K is to use liquid helium. Unfortunately, helium is a non-renewable and scarce natural resource, and uncertainties in supply and pricing are already significantly impacting research. One way around this problem is to use closed-cycle refrigerators which use compressors or pulse-tubes to achieve low temperatures. However, purchasing new instruments or retrofitting complex existing instruments with this technology is extremely expensive. We propose instead to purchase two helium reliquefiers that can be simply attached to our existing low temperature cryostats, enabling 100% recovery and recycling of helium during operation. The availability of these reliquefiers will immediately impact a recently awarded ARO funded project on two-dimensional magnetoelectric devices based on a newer class of layered materials, the chalcophosphates. For these studies, the ability to perform variable temperature experiments over extended periods of time is critical. The reliquefiers will also impact a number of other ongoing projects in the PI’s group that require continuous access to low temperatures for long periods of time, including experiments on complex oxides, superconducting hybrids, and quantum materials. In addition to the training of graduate students and post-docs, the PI has a strong record of involving undergraduates in ongoing research. A large number of undergraduates have been involved in our DoD funded research over the years, and it is expected that this participation will continue.