Itinerant-electron metamagnetic transition and giant magnetocaloric effect in La0.8Ce0.2Fe11.4Si1.6 compound

The itinerant-electron metamagnetic (IEM) transition and magnetocaloric effects (MCE's) in the La0.8Ce0.2Fe13-xSix (x=1.6,1.4,1.2,1.0) compounds have been investigated by x-ray powder diffraction and magnetic measurements. The La0.8Ce0.2Fe11.4Si1.6 compound exhibits giant values of the isothermal magnetic entropy change Delta S-M around the Curie temperature T-C similar to 186 K in low magnetic fields. The maximum value parallel to Delta S-M parallel to(max)similar to 78.29 J/kg K is under a field of 3 T. Such large MCE's are attributed to the sharp change of the magnetization, the field-induced IEM transition and a strong temperature dependence of the critical field B-C. The substitution of Ce for part of La in La0.8Ce0.2Fe11.4Si1.6 increases the value of a(T)c(T)/b(T)(2) and enhances the property of IEM. (c) 2006 American Institute of Physics.