Structural and Magnetic Properties of Cr<sup>3+ </sup>Doped Mg Ferrites

Abstract

The polycrystalline MgCrxFe2-xO4 ferrites (0.0 ? x ? 1.0) were prepared by conventional solid state ceramic sintering technique in air at 1300?C. X-ray diffraction experiments were carried out on all the samples in order to characterize the materials at room temperature. The X-ray diffraction patterns showed sharp peaks indicating the formation of single phased cubic spinel structure. The lattice parameters of the samples were determined from the X-ray diffraction data using Nelson-Riley extrapolation method. It was found that the lattice parameter decreased with increasing Cr concen- tration obeying Vegard’s law. Magnetic properties of the samples were measured using an Impedance Analyzer. Real and imaginary parts of the complex permeability, loss factor and quality factor were measured as the function of frequency at three different sintering temperatures 1250?C, 1300?C and 1350?C for all the samples in the frequency range 1 kHz to 13 MHz. Frequency stability of the real part of permeability increases with increasing Cr concentration and also with sintering temperature. Imaginary part of permeability decreases with increasing frequency and increased with increasing both of the Cr content and sintering temperature. Loss factor decreased with increasing frequency while the quality factor (Q) increased with increasing frequency for all the samples. The temperature de- pendence of initial permeability was measured for all the samples sintered at 1300?C. The Curie temperature (Tc) was determined from the -T curves. The values of Tc were found to be 733 K, 657 K, 583 K, 468 K, 400 K and 317 K for x = 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0, respectively

Magnetic Hysteresis and Curie Temperature in Nickel-Chromium Ferrites Synthesized by Sol-Gel Auto-Combustion Method

“…One can see that, for each examined ferrite composition, the magnetic permeability reaches a specific maximum value at a specific temperature and then drastically decreases. It was known [30] that the maximum of the initial magnetic permeability is observed at a temperature slightly below the Curie point. Therefore, the true Curie temperature of ferrites was determined by linearly extrapolating the steepest section in the dependence ( ) to the intersection with the abscissa axis.…”

Alternate current magnetic property characterization of nonstoichiometric zinc ferrite nanocrystals for inductor fabrication via a solution based process

“…8, it into the iron oxide NCs does not cause a decrease in efficiency. Since the RLF value is still lower than those of the sintered ferrite materials, 80,81 further investigation and optimization on the NCs are necessary to increase the energy efficiency.…”

Magnetic properties and structural analysis on spinel MnFe2O4 nanoparticles prepared via non‐aqueous microwave synthesis

“…[15,34] This can be correlated to spin canting phenomena and/or mixed valence. [35,36] Spin canting describes the phenomenon that especially the spins of surface ions feature different orientations leading to altered magnetic moments. This effect is especially observed in nanostructures due to the finite-size effect.…”