Efficient electron refrigeration using superconductor/spin-filter devices

Efficient electron-refrigeration based on a normal-metal/spin-filter/ superconductor junction is proposed and demonstrated theoretically. The spin-filtering effect leads to values of the cooling power much higher than in conventional normal-metal/nonmagnetic-insulator/superconductor coolers and allows for an efficient extraction of heat from the normal metal. We demonstrate that highly efficient cooling can be realized in both ballistic and diffusive multi-channel junctions in which the reduction of the electron temperature from 300 mK to around 50 mK can be achieved. Our results indicate the practical usefulness of spin-filters for efficiently cooling detectors, sensors, and quantum devices. © 2013 AIP Publishing LLC.This work was supported by the Topological Quantum Phenomena (No. 22103002) KAKENHI on Innovative Areas, the JSPS Institutional Program for Young Researcher Overseas Visits, the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement “INFERNOS” No. 308850, the Spanish Ministry of Economy and Competitiveness under Project FIS2011-28851-C02-02, the CSIC, and the European Social Fund under JAE-Predoc program.Peer Reviewe