Control of Working Temperature of Isothermal Magnetic Entropy Change in La0.8Nd0.2(Fe0.88Si0.12)13 by Hydrogen Absorption for Magnetic Refrigerants

La1-zNdz((Fe0.88Si0.02)(13) and their hydrides were investigated to obtain large magnetocaloric effects (MCEs) in a wide temperature range, including room temperature, for applications in magnetic refrigents. Since the magnetization change due to the itinerant-electron metamagentic (1EM) transition for La1-zNdz((Fe0.88Si0.02)(13) becomes larger with increasing z, the isothermal magnetic entropy change Delta S-m and the relative cooling power (RCP) are enhanced. In addition, the Curie temperatrue T-c of La0.8Nd0.2((Fe0.88Si0.12)(13) is increased from 193 to 319 K by hydrogen absorption, with the lEM transition. The maximum value of -AS., -Minn', in a magnetic field change of 2 T for La0.8Nd0.2((Fe0.88Si0.12)(13)H-1.1 is about 23 J/kg K at T-c = 288 K, which is larger than that of 19 J/ kg K at T-c = 276 K for La(Fe0.88Si0.12)(13)H-1.0. The value of RCP = 179 J/kg of the former is also larger than 160 J/ kg of the latter. It is concluded that the partial substitution of Nd improves MCEs in a wide temperautre range, including room temperature.