Switch for Magnetic Refrigeration with Surface Fabricated by Laser Inteference Lithography

The paper examines the problem of creating an alternative solid-state magnetic cooling technology using the magnetocaloric effect in rare-earth magnetic materials. Known gas cryoculi implement the thermodynamic Stirling (Gifford-McMahon) cycle with a high temperature difference achieved, but low efficiency of the cooling process. The best solid-state materials are, in principle, capable of increasing the efficiency of the thermodynamic process. However, in order to find the ideal efficiency, in a magnetocaloric solid-state refrigerator, it is necessary to turn to the Carnot cycle and study thermal manipulation in a vacuum with high speed and negligible losses. Thus, the problem of creating a thermal switch operating in a vacuum and strong magnetic fields is of primary importance. In this work, the concept of a solid-state magnetic refrigerator with thermal interfaces in the form of a vacuum gap with a surface modified by laser interference lithography (LIL) has been developed. A method for experimental determination of contact thermal conductivity (contact thermal resistance) of unsteady heat flux in a wide temperature range from 7 K to 325 K is described. A review of micro- and nanostructured surfaces for use as thermal interfaces in electronics and cryogenic engineering is provided. The prospect of using LIL modified thermo interfaces in thermal switches is noted.