Large magnetocaloric effects and thermal transport properties of La(FeSi)13 and their hydrides

La(FexSi1−x)13 exhibit an itinerant-electron metamagnetic (IEM) transition at relatively low applied magnetic fields just above the Curie temperature TC. Large magnetocaloric effects (MCEs) in terms of the isothermal temperature change ΔSm and the adiabatic temperature change ΔTad are followed by the IEM transition. The MCEs increase, while TC decreases with increasing Fe concentration. Therefore, TC of these compounds should be controlled up to room temperature from the viewpoint of practical applications. The working temperature as magnetic refrigerants is extended from about 185 to 330 K by adjusting hydrogen concentration. After hydrogen absorption, the MCEs as well as the thermal conductivity of La(FexSi1−x)13 and their hydrides exhibit excellent characteristics in the temperature range mentioned above. Consequently, the present compounds are one of the promising candidates for magnetic refrigerants working in a wide temperature range covering room temperature.