Structural, Magnetic, and Dielectric properties of Sr4Fe6O13 ferrite prepared of small crystallites

Magnetic properties, critical behaviors and magnetocaloric effect in non-stoichiometric spinel type Co1+xCrxFe2-xO4

The magnetic properties, magnetocaloric effect, and critical analysis of magnetic behavior of Co_1+xCr_xFe_2-xO₄ (x = 0.125, 0.250, 0.375, and 0.500) with a non-stoichiometric ratio are studied in detail. All the synthesized samples exhibit single-domain behavior. The Cr³⁺ associated with excess Co²⁺ led to tuning the magnetic moment, exchange interaction, magnetocrystalline anisotropy constant, and microwave frequency. The second-order magnetic phase transition has been confirmed from the Arrot and Arrot-Noakes plots for all the samples. The Cr³⁺ associated with excess Co²⁺ also tuned the magnetocaloric (MCE) properties showing the maximum relative cooling power of 156 J kg^-1, which is a higher value than that of previously reported Cr³⁺ substituted stoichiometric cobalt ferrite. The reliability of MCE and the nature of the magnetic phase transition of the investigated samples are confirmed by analyzing the critical exponent analysis, universal curve scaling, and scaling analysis of MCE.

Sol-Gel/Gel Casting Nanoarchitectonics of Hybrid Fe2O3–ZnO/PS-PEG Nanocomposites and Their Optomagnetic Properties

Polymer networks incorporated with iron and zinc oxide nanoparticles have superparamagnetic and electrical characteristics where it can be employed in a variety of significant applications. To achieve optimal distribution and connection of nanoparticles in various polymeric matrices, it is required to investigate their dispersion performance with varied contents and the impact on their physical characteristics. A controlled sol-gel method is used combined with gel casting to synthesize organic-inorganic nanocomposites of (ZnO)x(1 − x)Fe2O3 loaded within a polystyrene-polyethylene glycol matrix. The structural and morphological assembly of the hydrogen bonds between the inorganic and organic parts is verified using X-ray diffraction (XRD) and scanning/transmission electron microscope (SEM/TEM) for the synthesized nanocomposites. The existence of the Fe aggregates, Zn/Fe pairs, and organic molecules was also confirmed by FTIR spectra. Optical and magnetic properties were evaluated. The band gap, refractive index, optical dielectric constant, and optical electronegativity were extracted.

Magnetic properties, magnetocaloric effect, and critical behaviors in Co1-x Cr x Fe2O4

This research work focuses on the magnetic properties, nature of the magnetic phase transition, magnetocaloric effect, and critical scaling of magnetization of various Co1-x Cr x Fe2O4 (x = 0, 0.125, 0.25, 0.375, and 0.5). The tunability of the magnetic moment, exchange interactions, magnetocrystalline anisotropy constant, and microwave frequency using Cr3+ content has been found. The nature of the magnetic phase transitions for all the Cr3+ concentrations exhibits as second order which has been confirmed from the analysis of critical scaling, universal curve scaling, and scaling analysis of the magnetocaloric effect. The critical exponent analysis for all samples was performed from the modified Arrott-, and Kouvel-Fisher-plots. These critical analyses suggest that x = 0.125, 0.250, and 0.375 samples show reliable results in the magnetocaloric effect with relative cooling power (RCP) values in the range of 128-145 J kg-1. On the other hand, x = 0.00, and 0.500 samples exhibit inconsistent RCP values. The universal curve scaling also confirms the reliability of the magnetocaloric effect of the investigated samples.