Dielectic refrigerator using orientable defect dipoles

Abstract

This disclosure describes a dielectric refrigerator using orientable defect dipoles and operating between a high temperature, T.sub.h reservoir illustratively supplied by a Stirling cycle refrigerator (8.degree. K .ltoreq. T.sub.h .ltoreq. 20.degree. K) and a low temperature, T.sub.1, load, illustratively the liquid He cooling fluid for Josephson junction or other superconducting devices (2.degree. K .ltoreq. T.sub.1 .ltoreq. 6.degree. K). Exemplary practice of this invention provides cooling from the limit of a refrigerator based on the Stirling thermodynamic cycle (20 to 8.degree. K) to operating temperatures of common and useful superconductive devices (3 to 6.degree. K). Orientable electric dipoles of defects in electrically insulating materials, e.g., crystals, are utilized to provide cooling in the range from (8-20 K) to (2-6.degree. K). The following are particular considerations concerning the practice of this invention: use of LiF, MgO and BeO as host crystals; use of OH and/or NH.sub.2 as defects in LiF, and use of HF, HCl, HBr and/or NH as defects in MgO or BeO; mechanical or electromechanical means to make and break thermal contact between dielectric crystal and load and between load and reservoir; and use of thermal rectifiers to obviate the need for thermal switches in order to transfer heat from the load to the refrigerator material and thence to the reservoir.