Influence of Ni on the magnetocaloric effect in Nanoperm-type soft-magnetic amorphous alloys

• Preparation of melt spun amorphous Nanoperm soft-magnetic amorphous alloys with Ni.
• The magnetocaloric effect increases for 25% compared to the Ni-free sample.
• All magnetic entropy change curves show a master-curve behavior.
• The dependence of TC, ΔSMpk and RC does not follow a power law.

We have studied the influence of Ni on the magnetocaloric effect (MCE) in Nanoperm-type amorphous materials by investigating a series of Fe84−xNixZr6B10 alloys with x = 0, 2, 4 and 6. As expected, the Curie temperature increased with the amount of Ni from 427 K for x = 0 to 482 K for x = 6. The maximum magnetic entropy change (ΔSMpk) for an applied field of 1.4 T also increased, reaching a value of 1.52 J/K kg for x = 6, which is an increase of 25% compared to the Ni-free alloy. The refrigerant capacity first decreased for x = 2 and then increased, reaching a maximum value of 93 J/kg (ΔH = 1.4 T) for x = 6. For a 5 T field change, the value increased to 407 J/kg, which is higher than the 355 J/kg achieved with Gd5Ge1.9Si2Fe0.1. We confirmed the proposed “master curve” behavior for second-order magnetic transition (SOMT) alloys for the temperature dependence of ΔSM for different alloy compositions of the same series, which makes it easier and faster to find proper candidates for a magnetic refrigerator.