Effects of composition variation and hydrogenation on magnetocaloric properties of the (Gd

To identify promising magnetic refrigerant materials, we have studied the influence of composition variations and hydrogenation on the magnetocaloric effect (MCE) of the (Gd1-xTbx)Ni compounds. The end compositions of the series, Gd0.9Tb0.1Ni and Gd0.1Tb0.9Ni crystallize in orthorhombic CrB-type and...
Ausführliche Beschreibung

To identify promising magnetic refrigerant materials, we have studied the influence of composition variations and hydrogenation on the magnetocaloric effect (MCE) of the (Gd1-xTbx)Ni compounds. The end compositions of the series, Gd0.9Tb0.1Ni and Gd0.1Tb0.9Ni crystallize in orthorhombic CrB-type and monoclinic TbNi-type structures, respectively. Hydrogenation boosts the unit cell volume of (Gd,Tb)Ni by more than 20 % upon absorption of 4 at.H/f.u. Hydrogen absorption changes the structure type from TbNi to the CrB-type in Gd0.1Tb0.9Ni. Decrease of the Curie temperature in hydrides reaches ∼ 60 K. The magnetocaloric effect in (Gd,Tb)NiHy (y = 0 and 4) obtained by indirect method in the vicinity of TC revealed similar values of the maximum of specific isothermal entropy change -ΔST = 20.5 J kg−1 K−1 for Gd0.9Tb0.1Ni and its hydride Gd0.9Tb0.1NiH4 at μ0ΔH = 7 T. We show that the controlled synthesis of hydrides allows us to tailor the magnetocaloric effect in the multicomponent rare earth intermetallics and obtain materials with largely different TCs but with the same MCE values that are attractive for use in low-temperature magnetic cooling applications. Ausführliche Beschreibung