Hydrogenation-induced variation in crystal structure and heat capacity of magnetic regenerative material Er 3Ni

Abstract

In order to analyze the influence of hydrogenation on magnetic regenerative material Er 3Ni, the structures of Er 3Ni and its hydrides Er 3NiH x are tested by X-ray diffraction (XRD), and their magnetic properties and heat capacities are measured by a magnetic property measurement system (MPMS) and by a physical property measurement system (PPMS), respectively. The results show that different crystal structures can be formed by the hydrogenation at 293 K, while the Er 3NiH x does not go through magnetic transition above 2 K. The Er 3NiH x exhibits different specific heat features with that of original compound Er 3Ni, which could be attributed to the absence of magnetic transition and other effects caused by hydrogenation. The insertion of hydrogen atoms can lead to a larger specific heat than that of Er 3Ni in some certain temperature range.