Control of large magnetocaloric effects in metamagnetic La(FexSi1-x)13 compounds by hydrogenation

To obtain large magnetocaloric effects (MCEs) due to the itinerant-electron metamagnetic (IEM) transition in La(FexSi1-x)(13), the Curie temperature TC has been controlled by hydrogen absorption. In La(Fe0.88Si0.12)(13)H-y compounds, T-C = 195 K for y = 0.0 increases with increasing hydrogen concentration, resulting in T-C = 330 K for y = 1.6. Furthermore, the magnetic moment is also stabilized against temperature by hydrogen absorption. Since the IEM transition is preserved after hydrogenation, large MCEs of the magnetic entropy change Delta S-m and the adiabatic temperature change Delta T-ad have been observed around room temperature. A large value of Delta T-ad has been confirmed by a direct measurement in adiabatic magnetic field change for the La(Fe0.89Si0.11)(13)H-y (y = 0.0 and 1.6). Consequently, the La(FexSi1-x)(13) compounds and their hydrides are promising as high-performance magnetic refrigerants working in a wide range of temperature covering room temperature in relatively low applying magnetic fields. (c) 2005 Elsevier B.V. All rights reserved.