Magnetic properties and magnetocaloric effects in Gd1−xHoxNiIn intermetallic compounds

Magnetic properties and magnetocaloric effects (MCEs) of the intermetallic Gd1−xHoxNiIn (x=0−1) compounds have been evaluated by magnetization and heat capacity measurements. The Curie temperature TC can be tuned from near 100 K to 20 K by substituting Ho for Gd atoms. In addition, all the compounds with Ho atoms undergo two successive magnetic transitions with the decrease of temperature: a paramagnetic (PM) to ferromagnetic (FM) transition around TC and a spin-reorientation (SR) transition around 7−9 K. It is found that both transitions contribute to the magnetic entropy change (ΔSM). For a field change of 5 T, the maximum values of −ΔSM for Gd0.4Ho0.6NiIn are 6 J/kg K at Tt=9 K and 10 J/kg K at TC=52 K, respectively. These two −ΔSM peaks overlap partly and result in a wide working temperature range of MCE, and thus leading to the largest RC value of 443 J/kg in the Gd1−xHoxNiIn system.