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 T-C. Large magnetocaloric effects (MCEs) in terms of the isothermal temperature change Delta S-m and the adiabatic temperature change Delta T-ad are followed by the IEM transition. The MCEs increase, while T-C decreases with increasing Fe concentration. Therefore, T-C 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. (c) 2005 Elsevier B.V. All rights reserved.