Magnetism and magnetic entropy change of LaFe11.6Si1.4Cx (x=0−0.6) interstitial compounds

Chemically stable LaFe11.6Si1.4Cx (x=0−0.6) interstitial compounds were prepared. The Curie temperatures increases from 195 to 250 K with an increase in X from 0 to 0.6 due to obvious lattice expansion. The maximal magnetic entropy changes |ΔS| with a change in magnetic field of 0–5 T, are 24.8, 24.2, 18.8 and 12.1 J/kg K for x=0, 0.2, 0.4, and 0.6, respectively, notably exceeding that of Gd (|ΔS|∼9.8 J/kg K at TC=293 K). The magnetic transition varies from first order to second order with an increase in carbon concentration, which has a decisive influence on |ΔS|. The large |ΔS|, chemical stability, and low cost make LaFe11.4Si1.6Cx a promising candidate as a magnetic refrigerant in the corresponding temperature ranges.