Adjusting of the performance characteristics of the La(Fe,Si)13 compounds and their hydrides for multi-stimuli cooling cycle application

The use of multi-stimuli materials is a promising approach for increasing the cooling capacity of magnetic refrigerators. The working body undergoes both a magnetic field and an external compressive pressure during cooling. The proposed material must have outstanding magnetocaloric and mechanical properties. The magnetocaloric properties should provide a high adiabatic temperature change value in a limited field range. Mechanical stability at high pressures and adequate geometry are required to ensure high heat transfer values. The compounds La(Fe,Si)13 and their hydrides are the most suitable for the manufacture of such devices. They are able to work at both room and cryogenic temperatures. In the article, we present the results of direct measurements of the magnetocaloric effect and mechanical compression tests of the cast and hydrogenated La(Fe,Si)13Hδ rods. The samples were reinforced with a secondary alpha-iron phase, which ensured their mechanical integrity during hydrogenation and cycle performance. The addition of a secondary alpha-iron phase leads to a decrease in the magnetocaloric effect value. Therefore, we determine the optimal content of the secondary phase, which provides a balance between the caloric and mechanical alloy properties.