Tuning the magnetic and magnetocaloric properties and exponent analysis of amorphous Fe_xNi_80-xB₁₂Si₈ alloys with x = 2.4, 8 and 16

Abstract

The magnetic and magnetocaloric properties and exponent analysis near the phase transition temperature (T) of amorphous ribbons prepared by melt spinning process with nominal Fe_xNi_80−xB₁₂Si₈ alloys (x = 2.4, 8 and 16) have been widely investigated in this work. The amorphous state was checked by X-ray diffraction. From the Curie–Weiss law, the CW temperature (θ_P) and effective moment experimental (${\mu}_{\text{eff}}^{\text{exp}}$) are extracted. In addition, the investigation demonstrates that the phase transition from ferromagnetic (FM) to paramagnetic (PM) states is a second order. A phenomenological model applied to elucidate the magnetocaloric effect behaviour of compounds. The critical exponents (CE) are calculated using the Kouvel–Fisher approach, which is based on data from magnetic measurements around the T_C (Curie temperature). These exponents are produced close to mean field values. This is a signal of FM long-range order in these samples. A single equation of state is used to scale the magnetization below (T < T_C) and above (T > T_C). The reliability of the CE was tested by other different robust methods. Ultimately, the long-range ferromagnetic order in our system was essentially confirmed by the exchange interaction prediction J(r).