Enhancement of magnetocaloric effect in B-rich FeZrBCu amorphous alloys

Highlights: • Magnetic properties and magnetocaloric effect were studied in FeZrBCu glasses. • An increase was found in the magnetic entropy change for high B content. • This correlates well with the anomalous increase of the magnetic moment. • The effect is attributed to the highly attractive B-Zr interaction. • This effect can have an impact on increasing the refrigeration capacity. - Abstract: Magnetic properties and magnetocaloric effect were studied in the Fe_92−xZr₇B_xCu₁ amorphous alloy series (x = 0-23 at.%). Enhancement of the magnetocaloric effect was observed in the B-rich side (x > 15 at.%) which correlates well with the anomalous increase of the saturation magnetic moment per Fe atom in this concentration range. Research into Fe₂(B_1−yETM_y) amorphous alloys (ETM = Zr, Nb, Ti and V; y = 0-0.55 atomic fraction for Zr and to 0.25 atomic fraction for the rest) reveals an unexpected increase of the iron magnetic moment when early transition metals are substituted for B up to y = 0.1-0.25 atomic fraction. This behavior is attributed to the highly attractive B-ETM interaction. Similar mechanism is thought to explain the anomalous increase of the iron magnetic moment and hence the magnetocaloric effect in the boron-rich Fe_1−xZr₇B_xCu₁ amorphous alloys. Universal scaling of the magnetic entropy change curves is also used to detect differences between Fe_92−xZr₇B_xCu₁ alloys