Hydrogenation-induced variation in crystal structure and heat capacity of magnetic regenerative material Er3Ni

► The Er3Ni hydrogenation is experimentally studied to check the specific heat feature. ► The XRD, PPMS, MPMS are used to measure the properties of the hydride Er3NiHx. ► The effects of hydrogen atoms on structural and magnetic properties are analyzed. ► The relation between magnetic and specific heat properties is discussed.