Structure and magnetic properties of amorphous Fe-(Zr,Nb)-B melt spun alloys

In this work, we report the structure and magnetic behavior of an amorphous Fe₈₁Zr₅Nb₄B₁₀ melt-spun alloy. The radial distribution function (RDF) afforded the resolution of the nearest-neighbor configuration on the basis of the atom-pair distance information, for which the positions of each peak indicated the atom-to-atom separation involved for short-range ordering. The first peaks of RDF were attributed to the distances of B-B, Fe-Fe and Zr-Nb atomic pairs, indicating a glassy structure equivalent to a distorted bcc-Fe cluster. From magnetic measurements, a magnetic moment of 0.65 Bohr magneton per Fe atom was established, together with a Curie temperature of 334 K and an initial ac permeability of 550 for frequencies as high as 250 kHz. In addition, the magnetocaloric effect, quantified from isothermal magnetization measurements through the magnetic entropy variation, reached a maximum of 2.0 J/kg K for a magnetic field change of 2.0 T. - Highlights: • Amorphous Fe₈₁Zr₅Nb₄B₁₀ alloy was obtained by melt-spinning. • An atomic structure model is proposed to describe the structure of amorphous alloy. • The effective moment of the alloy is μ_eff=0.65μ_B per atom of Fe. • Accroding to Arrot plots, order-disorder magnetic transition is of second order-type. • Maximum magnetic entropy variation was of 2.0 J/kg K.