Investigating the structural, magnetic, magnetocaloric and critical behavior of Mg0.35Zn0.65Fe2O4 ferrite.

In this study, we successfully prepared the Mg 0.35 Zn 0.65 Fe 2 O 4 ferrite sample via standard solid-phase reaction and comprehensive studied its structure, magnetism, magnetocaloric effect and critical behavior. The XRD data refined by Rietveld technology confirms that the sample had a pure phase spinel structure. We conducted a magnetic study on the sample using SQUID and indicated that the sample' ferromagnetic curie temperature T c = 295 K, the paramagnetic curie temperature T P = 330 K, and the saturation magnetization can reach 125.41emu/g at an ultra-low temperature of 5 K. We tested the initial magnetization curve near the phase transition temperature (T c) from ferromagnetic (FM) to paramagnetic states (PM) and produced an Arrott plot that confirmed the presence of a secondary phase transition. The sample' maximum magnetic entropy change | Δ S M max | was 1.642 J/kg K and relative cooling power RCP was 185.2 J/kg in the external magnetic field H = 50 kOe. The critical parameter β, γ, δ, and T P were calculated using a Modified Arrott plot (MAP), Kouvel-Fisher (KF) plot and critical isotherm (CI) methods to study the type of magnetic order in the ferromagnetic state that corresponded to the magnetic state equation and mean field model. By analyzing the critical parameters, we obtained the ferromagnetic exchange integral constant J(r) ~ r −4.8498, which was between the 3D Heisenberg model and mean field models and very close to the mean field model, confirming that the long-range and short-range ferromagnetic orderly interactions coexisted with interaction phases and the long-range ferromagnetic orderly interaction dominates. [ABSTRACT FROM AUTHOR]