Effect of the introduction of H atoms on magnetic properties and magnetic entropy change in metamagnetic Heusler alloys Ni–Mn–In

Abstract

By hydrogen insertion into Ni51Mn49−xInx (x=16.2,16.6) Heusler alloys, the interstitial compounds Ni51Mn49−xInxHδ were fabricated. The introduction of H atoms does not change the L21 structure of the alloys but shifts martensitic temperature (TM) to lower temperature. Magnetic measurements indicated the hydrogenated Ni51Mn49−xInxHδ compounds retain the metamagnetic properties although the ferromagnetic behavior of martensitic phases is slightly enhanced due to the introduction of H atoms. The strong metamagnetic behaviors result in large magnetocaloric effect (MCE). By controlling H content an extended temperature range having large MCE can be achieved.