Enhanced magnetic properties at low temperature of Mn substituted Ni-Zn mixed ferrite doped with Gd ions for magnetoresistive applications

Gora

Bangladesh J. Sci. Ind. Res.

et al. 2022

The current study unravels the structural, optical band gap and magnetic characteristics of rare-earth (RE) gadolinium (Gd) substituted CoGdxFe2-xO4 (x= 0.00 - 0.10, in the interval of 0.02) nanocrystallites synthesized by the sol-gel self-ignition route. The XRD analysis and Rietveld refinement confirmed the existence of a single cubic phase with a crystallite size of ~15-21 nm range, further confirmed by HRTEM results. SEM images confirmed the well-known nano-size morphology for all the samples. The magnetization measurements show a hard ferromagnetic nature for all specimens within the temperature range of 20-300K. Coercivity, remanent, and saturation magnetization monotonically increased with a reduction in temperature from 300K to 20K. UV-Vis absorbance results show that the band gap energy of CoFe2O4 nanoparticles (NPs) decreases with increasing Gd3+ ion doping and have band gap energy values of 2.47, 2.15, 2,02, 2.00, 1.43 and 1.95 eV for x= 0.00, 0.02, 0.04, 0.06, 0.08, 0.10, respectively in CoGdxFe2-xO4 nanoferrites. The present study reveals that structural, optical band gap and magnetic properties could be altered by monitoring the quantity of gadolinium in cobalt nanoferrites. Bangladesh J. Sci. Ind. Res. 57(3), 173-186, 2022

Section: Table II Magnetic Parameters Formentioning

confidence: 82%

Reitveld refinement, structural, optical band gap and low-temperature magnetic characterization of Gd3+ doped spinel cubic CoFe2O4 nanoparticles

Gora

Bangladesh J. Sci. Ind. Res.

et al. 2022

ECS J. Solid State Sci. Technol.

“…The distribution of cations for the prepared samples is suggested based on the reports available in the literature. 6,7 It is noted that the smaller ions such as Zn 2+ ions only occupy the smaller spaces of the lattice, hence, Zn 2+ ions only occupy the tetrahedral sites because the tetrahedral (A) sites are smaller than those at the octahedral [B] sites in the spinel ferrites and Co 2+ ions occupy the octahedral sites. 1,6,7 On the other hand, the Mn 2+ ions get distributed over tetrahedral sites (80%) and octahedral sites (20%).…”

Section: Resultsmentioning

confidence: 99%

“…6,7 It is noted that the smaller ions such as Zn 2+ ions only occupy the smaller spaces of the lattice, hence, Zn 2+ ions only occupy the tetrahedral sites because the tetrahedral (A) sites are smaller than those at the octahedral [B] sites in the spinel ferrites and Co 2+ ions occupy the octahedral sites. 1,6,7 On the other hand, the Mn 2+ ions get distributed over tetrahedral sites (80%) and octahedral sites (20%). 6,7 The distribution of cations proposed according to the study 6 is as follows: [Zn 0.2 Mn 0.8x Fe 0.8-0.8x ] A [Co 0.8−x Mn 0.2x Fe 1.2+0.8x ] B O 4 .…”

Section: Resultsmentioning

confidence: 99%

Effect of Mn²⁺ Substitution on Structural and Magnetic Properties of Co-Zn Ferrite

Rady,

Reda Abd El-salam,

ELFadaly

et al. 2023

Co0.8-x Mnx Zn0.2 Fe2O4 (x = 0.0, 0.1, 0.2, and 0.3) was prepared using the coprecipitation method. We investigated the effect of the Mn+2 substitution on the structural and magnetic properties. X-ray analysis revealed formation of single phase spinel cubic ferrite nanoparticles unaccompanied by secondary phases while the Morphology studies done using scanning electron microscopy show spherical shaped nanoparticles which are agglomerated. The energy-dispersive X-ray analysis confirmed the expected stoichiometry. The measurements of the magnetic parameters, using VSM, were performed at room temperature. M-H loops have shown that the prepared samples exhibit soft ferrimagnetism. The saturation magnetization was found to decrease by increasing the Mn content. The magnetic moments that were estimated from measured magnetic parameters and from the cation distribution over A and B sites on the basis of Neel’s two sublattice model of ferrimagnetism, were noted in all the samples. Based on which we obtained an improvement in the magnetic properties of the prepared samples, that made them suitable for use in high-frequency applications ascribed to the Mn ions’ substitution.

Sixth International Conference on Intelligent Computing, Communication, and Devices (ICCD 2023)

“…The Hc shown in Figure 4(b) drop as temperature increases from 98.2 to 65.9 Oe, meaning a ruduction in the required field of demagnetizing, which is due to the growth of the crystals 46 . Normally, Hc has inverse relationship to the crystal size, according to the equation 47,48 .…”

Section: Resultsmentioning

confidence: 99%

Temperature tailored magneto-dielectric properties of Cd-substituting Mg-based ferrite ceramics for miniaturized VHF antennas

Gan

2023

The microstructure formation and structural regulation of Mg-Cd ferrites (Cd0.15Mg0.85Fe2O4) with 5% Bi2O3 addition at different sintering temperatures (880, 900, 920, and 940 °C) werer invsetigated for application in VHF antennas. The changes including microstructure, phase composition, magnetic and dielectric properties were mainly characterized. It was found that increasing temperature resulted in superior microstructure with accrescent grain size and denser arrangement. XRD patterns revealed normal spinel phase and a secondary phase of Bi compound. Meanwhile, a reinforcement of the magnetization including increased saturation magnetization (from 37.8 to 46.6 emu/g) and dropped coercivity (from 98.2 to 65.9 Oe) were obtained through hysteresis loops. A slight increment of μ' and ' were measured over a broad frequency range in VHF bands. Therefore, excellent magneto-dielectric properties of the proposed ferrites were obtained. In addition, low magnetic losses (tan δμ ~10 -2) and dielectric losses (tan δμ ~10 -3) indicating low power loss in operation. It is foreseeable that these properties of the proposed ferrites would behave well in miniaturized VHF antennas.