Study of the magnetocaloric effect of metals

Abstract

In the context of increasing requirements for environmental friendliness and energy efficiency of modern technologies, the creation of compact, safe, and reliable refrigeration systems operating at room temperature is becoming an extremely urgent task. Traditional cooling methods are accompanied by the leakage of refrigerants, contributing to the destruction of the ozone layer and global warming. One of the most promising alternatives is the magnetic cooling technology based on the magnetocaloric effect (MCE). Perovskite manganites, which have the ability to vary the temperature of phase transitions and are highly economically accessible, are of particular interest. However, existing studies are primarily based on indirect methods of MEI measurement, which reduces the reliability of the obtained data. This work emphasizes the need for direct adiabatic temperature measurements when the magnetic field changes in manganites of various compositions. Approaches to increasing Curie temperature through ion substitution are also considered, heat transfer and relaxation processes are analyzed, and models of magnetic refrigeration machines using solid and liquid working bodies are discussed. The presented theoretical analysis and generalization of experimental data are aimed at developing effective magnetic coolers suitable for use at room temperature.