Realization of quantum Hall effect in closed cycle refrigerators

Today a quantum Hall resistance standard (QHR) is realized in measurement setups with external supply of liquid helium. Operation costs due to helium prices and/or infrastructure needed to recycle evaporated helium gas are significant. The discovery of Quantum Hall effect in graphene made possible the measurement setup without an external supply of liquid helium. Such a setup could lead to cost-saving dissemination of intrinsically referenced resistance standards to all end-users relying on electrical measurements. Two setups based on closed cycle of helium were tested and experiment results are discussed.