Magnetic Properties Research Articles

Influence of cerium doping on the magnetic properties of a nanometric cobalt-zinc mixed ferrite

This study investigates the influence of cerium doping on the magnetic properties of nanometric-sized particles of a cobalt-zinc mixed ferrite with stoichiometric formula Co0.6Zn0.4Fe2O4. The effect of cerium doping was studied by producing a ferrite with the stoichiometric formula Co0.6Zn0.4Fe1.95Ce0.05O4 and comparing its magnetic properties with those of undoped cobalt-zinc ferrite and other ferrites. The samples were synthesized by sol-gel combustion and characterized by X-ray diffraction (XRD), vibrating-sample magnetometry (VSM) and ferromagnetic resonance (FMR). The XRD results confirm the synthesis of ferrite, the VSM results show that the saturation magnetization decreases with cerium doping and the FMR results show that the magnetocrystalline anisotropy decreases with cerium doping. Comparison with other ferrites suggests that doping with 5% cerium does not significantly decrease the microwave absorption of cobalt-zinc ferrite while protecting healthy cells in hyperthermy.

Contribution to the study of the CoFeTi Asquaternary Heusler material's structural, electronic, and magnetic properties

By simulating the structural, electronic, and magnetic properties of the QuateryCoFeTiAs Heusler compound, we presented a theoretical investigation in this work The calculations were performed using the generalized gradient (GGA) approximation and the WIEN2k code's application of the augmented plane wave method (FP-LAPW)which is based on density functional formalism (DFT). The results are consistent with important theoretical calculations.Our results showed that this compound conforms with the (Slater-Pauling) Mtot = (ZT - 24) μB rule and is a half-metallic material.

Strain engineering to tune the damping and magnetism in epitaxial spinel ferrite thin films by miscut substrate

Low-damping magnetic insulators like LiFe5O8 have gained considerable attention in recent years for their exceptional properties such as low energy loss and high gyromagnetic ratio, making them suitable in microwave and spintronic fields. However, due to factors such as crystalline quality and stress, the damping behavior of LiFe5O8 thin films falls below expectations. In this work, we utilize miscut substrate to modulate the structure and magnetic properties of LiFe5O8 films. We found that miscut angles can improve the crystalline quality of the film. However, a miscut angle of 6° resulted in a phase transition from tetragonal to orthorhombic in the LiFe5O8 phase. In particular, the out-of-plane ferromagnetic resonance linewidth of the orthorhombic LiFe5O8 (LFO) film was significantly reduced compared to that of the tetragonal LFO film on a non-miscut substrate, which could be attributed to the structural change. The orthorhombic LFO film also exhibited lower damping and a higher in-plane remanence ratio, indicating superior microwave magnetic properties. These findings suggest that miscut strain could be a viable method for improving the microwave magnetism of LFO films.

Contribution to the study of the CoFeTi Asquaternary Heusler material's structural, electronic, and magnetic properties

By simulating the structural, electronic, and magnetic properties of the QuateryCoFeTiAs Heusler compound, we presented a theoretical investigation in this work The calculations were performed using the generalized gradient (GGA) approximation and the WIEN2k code's application of the augmented plane wave method (FP-LAPW)which is based on density functional formalism (DFT). The results are consistent with important theoretical calculations.Our results showed that this compound conforms with the (Slater-Pauling) Mtot = (ZT - 24) μB rule and is a half-metallic material.

Thermal and Mechanical Vibration Response of Auxetic Core Sandwich Smart Nanoplate

This study explores a new nanoplate design's thermal and mechanical properties, including an auxetic core with a negative Poisson ratio. The core is between face plates made of barium–cobalt, which possess magnetoelectroelastic properties. The analysis centers on the parameters θ, β1, and β2 to clarify their influence on the nanoplate's performance. The evaluations of the nanoplate's thermal, electrical, and magnetic properties showcase its remarkable versatility and sensitivity. Incorporating magnetoelectroelastic face plates improves the multifunctionality of the nanoplate, making it a highly promising option for use in smart technologies. The findings offer valuable insights into the distinctive features of auxetic core structures, significantly enhancing the comprehension of these materials. This research emphasizes the potential for creating groundbreaking applications in fields like aerospace engineering and advanced electronics, where versatile and adaptable materials play a vital role. This study contributes to the broader knowledge of auxetic materials and their practical implementation in cutting‐edge technological solutions by exploring the interplay between thermal, mechanical, and magnetoelectroelastic properties.

Enhancement of the magneto-electronic properties by GGA and TB-mBJ approaches for KMgO3 perovskite oxide

We investigate the structural, elastic, electronic and magnetic properties of KMgO3. First-principal calculations, based on the formalism of the density functional theory (DFT) and the method of full potential augmented and linearized plane waves (FP-LAPW) implemented in the Wien2k code. The exchange and correlation effects were treated by the following two approximations: generalized gradient approximation (GGA) and Tran-Blaha modified beck Johnson (TB-mBJ) potentials. After analyzing the obtained structural parameters, the results revealed that KMgO3compound is most stable in its ferromagnetic configuration. The formation energy value showed that this compound can be experimentally synthesized. Furthermore, the calculated band structures, and density of states (DOSs) indicate the half-metallic behavior of KMgO3. We found also that the total magnetic moment is an integer value of 3μBwhich confirms the half-metallic character. The magnetic moment specially issues from the spin-polarization of p electrons of O atoms.

Investigation of superparamagnetic iron oxide nanoparticles in air environment for elevated saturation magnetization

Abstract Iron oxide nanoparticles have garnered interest for their unique properties and wide application areas. For applications, superparamagnetic nanoparticles are required so that they can be magnetized by an external magnetic field and rapidly demagnetize again when the field is removed. High saturation magnetization, Ms is also required for applications to provide easy magnetic control over separation and targeting. For magnetically controlled applications, superparamagnetic iron oxide nanoparticles with a high Ms are important. In this study, superparamagnetic iron oxide nanoparticles were co-precipitated under air atmosphere and the effects of alkali concentration, stirring rate and reaction time on the structural and related magnetic properties were investigated to obtain the high Ms for each parameter. According to the structural results, it is challenging to obtain magnetite nanoparticles under air atmosphere due to oxidizing effect. The increase of Ms values with the increase of alkali concentration may come from the phase of the samples although the crystal size of the nanoparticles is getting smaller. It can be said that there is an optimum stirring rate to obtain the highest Ms under air atmosphere rather than an uptrend/downtrend. The maximum Ms of 69.2 emu/g was obtained for superparamagnetic iron oxide nanoparticles synthesized at 700 rpm. With the increase of reaction time, magnetic size of the nanoparticles is observed to decrease in contrast with the increase of physical particle size. The maximum Ms value for the reaction time parameter is 67.3 emu/g at 15 minutes. Due to their high Ms values and superparamagnetic nature, the nanoparticles synthesized under study may find use in magnetic separation, water purification, and other related fields.

Effects of inter-granular Sn on transport and magnetic properties of polycrystalline GdBCO superconductors

Effects of inter-granular Sn on transport and magnetic properties of polycrystalline GdBCO superconductors

Effects of inter-granular Sn on transport and magnetic properties of polycrystalline GdBCO superconductors

Effects of inter-granular Sn on transport and magnetic properties of polycrystalline GdBCO superconductors

Cytotoxicity and Genotoxicity Effects of a Magnetic Zeolite Composite in Daphnia magna (Straus, 1820)

Zeolite type 5A combined with the magnetic properties of maghemite nanoparticles facilitate the rapid absorption of heavy metals, which makes them an interesting proposal for the remediation of water contaminated with lead and arsenic. However, the physicochemical analysis related to concentration and size for the use of this magnetic zeolite composite (MZ0) in water bodies and the possible toxicological effects on aquatic fauna has not yet been carried out. The main objective of the research work is to determine lethal concentrations that cause damage to Daphnia magna based on LC50 tests, morphology, reproductive rate, and quantification of the expression of three genes closely involved in the morphological development of vital structures (Glass, NinaE, Pph13). To achieve this objective, populations of neonates and young individuals were used, and results showed that the LC50 for neonates was 11,314 mg L−1, while for young individuals, it was 0.0310 mg L−1. Damage to morphological development was evidenced by a decrease in eye size in neonates, an increase in eye size in young individuals, variations in the size of the caudal spine for both age groups, and slight increases in the heart size, body, and antenna for both age groups. The reproductive rate of neonates was not affected by the lower concentrations of MZ0, while in young individuals, the reproductive rate decreased by more than 50% from the minimum exposure concentration of MZ0. And for both ages, Glass gene expression levels decreased as the MZ0 concentration increased. Also, the MZ0 evidenced its affinity for the exoskeleton of D. magna, which was observed using both light microscopy and electron microscopy. It is concluded that MZ0 did not generate significant damage in the mortality, morphology, reproductive rate, or gene expression in D. magna at lower concentrations, demonstrating the importance of evaluating the possible impacts on different life stages of the cladoceran.

Influence of synthesis method on structural, microstructural, and magnetic properties of Bi0.5La0.5FeO3 ceramics

Influence of synthesis method on structural, microstructural, and magnetic properties of Bi0.5La0.5FeO3 ceramics

Determination of half metallicity behavior of quaternary heusler alloy crcoscga

In this work, the theoretical study through the calculations of the structural, electronic and magnetic properties of quaternary heusler compound CrCoScGa, using wien2k code, is reported. We adopted the generalized gradient approximation (GGA) to estimate the exchange correlation potential. The negative value of the formation energy shows that CrCoScGa compound have a high structural stability in the type III structure feromagnetic phase, so it can be experimentaly synthetised. According to our electronic calculations, CrCoScGa is a half-metallic ferromagnet (HMF) with a half-metallic gap of 0.22 eV. The total magnetic moment of 3µB, mainly originated from Cr and Co atoms, makes this alloy as a spintronic material.

Cytotoxicity and Genotoxicity Effects of a Magnetic Zeolite Composite in Daphnia magna (Straus, 1820)

Zeolite type 5A combined with the magnetic properties of maghemite nanoparticles facilitate the rapid absorption of heavy metals, which makes them an interesting proposal for the remediation of water contaminated with lead and arsenic. However, the physicochemical analysis related to concentration and size for the use of this magnetic zeolite composite (MZ0) in water bodies and the possible toxicological effects on aquatic fauna has not yet been carried out. The main objective of the research work is to determine lethal concentrations that cause damage to Daphnia magna based on LC50 tests, morphology, reproductive rate, and quantification of the expression of three genes closely involved in the morphological development of vital structures (Glass, NinaE, Pph13). To achieve this objective, populations of neonates and young individuals were used, and results showed that the LC50 for neonates was 11,314 mg L−1, while for young individuals, it was 0.0310 mg L−1. Damage to morphological development was evidenced by a decrease in eye size in neonates, an increase in eye size in young individuals, variations in the size of the caudal spine for both age groups, and slight increases in the heart size, body, and antenna for both age groups. The reproductive rate of neonates was not affected by the lower concentrations of MZ0, while in young individuals, the reproductive rate decreased by more than 50% from the minimum exposure concentration of MZ0. And for both ages, Glass gene expression levels decreased as the MZ0 concentration increased. Also, the MZ0 evidenced its affinity for the exoskeleton of D. magna, which was observed using both light microscopy and electron microscopy. It is concluded that MZ0 did not generate significant damage in the mortality, morphology, reproductive rate, or gene expression in D. magna at lower concentrations, demonstrating the importance of evaluating the possible impacts on different life stages of the cladoceran.

Influence of synthesis method on structural, microstructural, and magnetic properties of Bi0.5La0.5FeO3 ceramics

Influence of synthesis method on structural, microstructural, and magnetic properties of Bi0.5La0.5FeO3 ceramics

Determination of half metallicity behavior of quaternary heusler alloy crcoscga

In this work, the theoretical study through the calculations of the structural, electronic and magnetic properties of quaternary heusler compound CrCoScGa, using wien2k code, is reported. We adopted the generalized gradient approximation (GGA) to estimate the exchange correlation potential. The negative value of the formation energy shows that CrCoScGa compound have a high structural stability in the type III structure feromagnetic phase, so it can be experimentaly synthetised. According to our electronic calculations, CrCoScGa is a half-metallic ferromagnet (HMF) with a half-metallic gap of 0.22 eV. The total magnetic moment of 3µB, mainly originated from Cr and Co atoms, makes this alloy as a spintronic material.

Investigation of superparamagnetic iron oxide nanoparticles in air environment for elevated saturation magnetization

Abstract Iron oxide nanoparticles have garnered interest for their unique properties and wide application areas. For applications, superparamagnetic nanoparticles are required so that they can be magnetized by an external magnetic field and rapidly demagnetize again when the field is removed. High saturation magnetization, Ms is also required for applications to provide easy magnetic control over separation and targeting. For magnetically controlled applications, superparamagnetic iron oxide nanoparticles with a high Ms are important. In this study, superparamagnetic iron oxide nanoparticles were co-precipitated under air atmosphere and the effects of alkali concentration, stirring rate and reaction time on the structural and related magnetic properties were investigated to obtain the high Ms for each parameter. According to the structural results, it is challenging to obtain magnetite nanoparticles under air atmosphere due to oxidizing effect. The increase of Ms values with the increase of alkali concentration may come from the phase of the samples although the crystal size of the nanoparticles is getting smaller. It can be said that there is an optimum stirring rate to obtain the highest Ms under air atmosphere rather than an uptrend/downtrend. The maximum Ms of 69.2 emu/g was obtained for superparamagnetic iron oxide nanoparticles synthesized at 700 rpm. With the increase of reaction time, magnetic size of the nanoparticles is observed to decrease in contrast with the increase of physical particle size. The maximum Ms value for the reaction time parameter is 67.3 emu/g at 15 minutes. Due to their high Ms values and superparamagnetic nature, the nanoparticles synthesized under study may find use in magnetic separation, water purification, and other related fields.

Improved High Frequency Soft Magnetic Properties in FeSiBCuNb Nanocrystalline Alloys Induced by Additional Low Magnetic Field Annealing

Improved High Frequency Soft Magnetic Properties in FeSiBCuNb Nanocrystalline Alloys Induced by Additional Low Magnetic Field Annealing

Enhancement of the magneto-electronic properties by GGA and TB-mBJ approaches for KMgO3 perovskite oxide

We investigate the structural, elastic, electronic and magnetic properties of KMgO3. First-principal calculations, based on the formalism of the density functional theory (DFT) and the method of full potential augmented and linearized plane waves (FP-LAPW) implemented in the Wien2k code. The exchange and correlation effects were treated by the following two approximations: generalized gradient approximation (GGA) and Tran-Blaha modified beck Johnson (TB-mBJ) potentials. After analyzing the obtained structural parameters, the results revealed that KMgO3compound is most stable in its ferromagnetic configuration. The formation energy value showed that this compound can be experimentally synthesized. Furthermore, the calculated band structures, and density of states (DOSs) indicate the half-metallic behavior of KMgO3. We found also that the total magnetic moment is an integer value of 3μBwhich confirms the half-metallic character. The magnetic moment specially issues from the spin-polarization of p electrons of O atoms.

An equivalent and simplified approach for acoustic noise prediction in a PM synchronous motor based on the semi‐analytical‐FEM model

AbstractThe vibration and acoustic noise of a permanent‐magnet synchronous motor are analysed and evaluated. Acoustic noise sound levels, their prominent frequencies, and the noisiest motor speed range are predicted. According to many resources, the radial vibration of the stator system due to the magnetic attraction between rotor permanent magnets and stator iron teeth is the main reason for the acoustic noise propagation of the PMSMs. The dominant orders of the spatial circumferential harmonics of the radial magnetic forces (RMFs) have been investigated and compared. The complete and complicated mechanical components, materials, and harmonics of the magnetic forces of the motor and their interaction are simplified and equalised to a vibration model, which consists of the interaction between the stator system and the dominant harmonic orders of the RMFs. Based on this approach, the simplest and most adequate semi‐analytical‐FEM model for noise prediction in PMSMs is proposed. This model, in addition to simplification, clarifies the role of the main mechanical and electromagnetic origins of noise generation. The acoustic noise prediction, using the proposed method has been compared with the experimental results. There is a proper agreement between the analytical, the FEM, and measurement results.

Magnetic and magnetostrictive properties of Cu-doped cobalt ferrite

The Cu-doped cobalt ferrites CuxCo1-xFe2O4 (CCFO) were synthesized by a glycine-nitrate sol-gel auto-combustion method and investigated for structural, magnetic and magnetostrictive properties. X-ray diffraction and scanning electron microscopy analysis revealed the formation of single cubic-spinel phase for all the as-prepared powders, followed by the sintered samples with grain sizes around 2.5 µm. The variation in stoichiometric composition can be used to tailor magnetic and magnetostrictive properties. Saturation magnetization MS decreases from 84.8 to 60.4 emu/g with increasing Cu content from x = 0.0 to x = 0.50, accompanied with a reduction in coercivity HC from 1.21 to 0.41 kOe. The introduction Cu into CFO is conductive to the decline in magnetocrystalline anisotropy, giving rise to an improvement in magnetostriction at low applied fields. An optimized composition in the CuxCo1-xFe2O4 ferrites is found to be around x = 0.30, achieving good magnetoelastic properties, i.e., a large saturation magnetostriction (–λS ∼ 240 ppm), a high strain sensitivity (–dλ/dH ∼ 1.44 nm/A), as well as a low magnetocrystalline anisotropy coefficient (K1 ∼ 3.7 × 106 erg/cm3). The excellent magnetoelastic properties and the combination in a facile synthesis process for sintered polycrystalline ferrites, suggest promising prospects in magnetostriction applications.