Itinerant-electron metamagnetic transition and large magnetocaloric effects in La(FexSi1-x)13 compounds and their hydrides -: art. no. 104416

The itinerant-electron metamagnetic (IEM) transition and magnetocaloric effects (MCE's) in the La(FexSi1-x)(13) and La(FexSi1-x)(13)H-y compounds have been investigated. The La(FexSi1-x)(13) compounds exhibit large values of both the isothermal entropy change DeltaS(m) and the adiabatic temperature change DeltaT(ad) around the Curie temperature T-C in relatively low magnetic fields. Such large MCE's are explained by a large magnetization change at T-C and a strong temperature dependence of the critical field B-C for the IEM transition. By hydrogen absorption into the compounds, T-C is increased up to about 330 K, keeping the metamagnetic transition properties. Accordingly, the extension of the working temperature range having the large MCE's in relatively low magnetic fields is demonstrated by controlling y in the La(FexSi1-x)(13)H-y compounds. The correlation between the increase of T-C and the large MCE's in the La(FexSi1-x)(13)H-y compounds is discussed by taking the magnetovolume effects into consideration.