Influence of gadolinium and dysprosium substitution on magnetic properties and magnetocaloric effect of Fe78−xRExSi4Nb5B12Cu1 amorphous alloys

Abstract

Amorphous Fe78−xRExSi4Nb5B12Cu1 (RE = Gd, Dy) ribbons with different RE contents were prepared by melt spinning to investigate the effect of heavy rare earth (Gd, Dy) substitution on the hyperfine structure, magnetic properties and magnetocaloric effect. The Curie temperature of RE substituted alloys, hyperfine field and magnetic moments of Fe atoms initially increase up to 1 at% RE content and then decrease monotonously for increasing RE content up to 10 at%. The dependence of magnetic entropy change (–ΔSM) and refrigeration capacity (RC) of the alloys on RE contents displays the same tendency. The RCAREA values of the alloys substituted with 1 at% Gd and Dy are similar to those of recently reported Fe-based metallic glasses with enhanced RC values compared with those of Gd5Ge1.9Si2Fe0.1. Enhanced –ΔSM and RC values, negligible coercive force and hysteresis commonly make these Fe78−xRExSi4Nb5B12Cu1 amorphous alloys as low-cost candidates for high-temperature magnetic refrigeration.