Magnetic Properties Of Nd Research Articles

Investigation for the Impact of Grain Boundary Diffusion Direction on the Magnetic Properties of Nd–Fe–B Permanent Magnets

Investigation for the Impact of Grain Boundary Diffusion Direction on the Magnetic Properties of Nd–Fe–B Permanent Magnets

Lanthanide-based F-MOFs: Structure, hydrolytic stability, spectral and magnetic properties

A series of five novel lanthanide-based fluorinated metal-organic frameworks (Ln-F-MOFs) have been synthesized under solvothermal conditions by the reaction of 3,3′-bis(trifluoromethyl)-[1,1′-biphenyl]-4,4′-dicarboxylic acid (H2L) and lanthanide Ln(III) ions (Ln(III)La, Ce, Pr, Nd and Eu). Powder X-ray diffraction (PXRD) analysis revealed that all prepared complexes are isostructural. A single-crystal X-ray crystallographic study of one representative of the isostructural group, namely {[La2(L)3(DMF)2(H2O)2]}n showed, that compound crystallizes in a triclinic system with space group P-1. The lattice parameter values are a = 8.563(2) Å, b = 13.199(3) Å, c = 16.008(4) Å, α = 104.588(7) °, β = 92.904(7) ° and γ = 92.717(7) °, with two formula units in the unit cell. The overall structure is formed by 2D polymeric layers, which are arranged into a semi-3D supramolecular structure through hydrogen bonds and other intramolecular interactions. The study of the hydrophobic properties of the complexes showed that the complexes exhibit surface hydrophobicity with a “rose petal effect” and a contact angle of approximately 107°. However, the structures are not hydrolytically stable in the long term and the structure starts to delaminate after two days in water. This is a manifestation of the fact that the complexes do not form a 3D polymer network, it is made up of 2D layers connected only by weak non-bonding interactions. The photoluminescence properties of the Ln(III) complexes are determined by the characteristic 5d-4f or 4f-4f electron transitions for the individual lanthanide ions. The magnetic properties of Nd(III), Pr(III) and Eu(III) variants were studied. The magnetic properties of {[Pr2(L)3(DMF)2(H2O)2]}n are characterized by the presence of a low-lying quasi-doublet with 15.6 cm−1 energy splitting, whereas Eu(III) variant is nonmagnetic at low temperatures, but the magnetic 7F1 state is accessible by thermal excitation. For Nd(III) complex, the X-band EPR measurements were performed. Since 1D channels with dimensions of 4.90 × 7.23 Å2 are present within the structure, the adsorption of N2, CO2 and H2 gases was also studied.

Signature of spin reorientation in dielectric and magnetic properties of Nd0.5Dy0.5FeO3 thin films

We present an analysis of the thin film Nd0.5Dy0.5FeO3/Si, focusing on its spin reorientation, dielectric, and magnetic characteristics. Exploring spin reorientation involves assessing dielectric and magnetic attributes across temperatures ranging from 2 to 300 K, at different applied frequencies. At temperatures between 34 and 24 K, a spin reorientation phenomenon is observed at a frequency of 10 kHz. As the applied frequency increases, the region of spin reorientation shifts towards higher temperatures. At 2 MHz, this region shifts to the temperature range from 30 to 45 K. This behaviour of the spin reorientation and shift in the spin reorientation region is further validated by AC Susceptibility data. By examining the magnetic order within the antiferromagnetic thin film, this study introduces an innovative approach to magnetic order investigation using dielectric properties.

Effect of Annealing Temperature on Grain Boundary Structure and Magnetic Properties of Nd–Ce–Gd–Fe–B Sintered Magnet

Post-sinter annealing plays an important role in optimizing grain boundary phases of Nd-Fe-B magnets. The sintered magnet is usually processed by two-step annealing, which consists of a high-temperature annealing (first-step annealing) followed by a low-temperature annealing (second-step annealing). In this work, the magnetic properties and microstructure of Nd-Ce-Gd-Fe-B magnets have been investigated by different second-step annealing temperatures. Compared with the magnet annealed at 420 °C, the knee coercivity ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">H</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">k</sub> ) of the 460 °C annealed magnet was increased by 156.7 kA/m, and the squareness factor was improved significantly from 0.85 to 0.98. The volume fraction of RE-rich (RE: rare earth) phases in the magnet has increased after second-step annealing at 460 °C. Microstructural analysis showed that the grain boundary layers in the 460 °C annealed magnets were thicker and evenly distributed around RE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Fe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">14</sub> B grains, which was helpful to decrease the exchange-coupling between RE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Fe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">14</sub> B grains and therefore enhance the coercivity.

Highly efficient lead removal from water by Nd0.90Ho0.10FeO3 nanoparticles and studying their optical and magnetic properties

Ho-doped NdFeO3 was synthesized using the citrate method. The X-ray diffraction (XRD) illustrated that Nd0.90Ho0.10FeO3 was crystalline at the nanoscale, with a crystallite size of 39.136 nm. The field emission scanning electron microscope (FESEM) illustrated the porous nature of Nd0.90Ho0.10FeO3, which increases the active sites to absorb the heavy metals on the sample surface. Energy-dispersive X-ray (EDX) data assures the prepared sample has the chemical formula Nd0.90Ho0.10FeO3. The magnetic properties of Nd0.90Ho0.10FeO3 were determined using the magnetization hysteresis loop and Faraday’s method. Many magnetic parameters of the sample have been discussed, such as the coercive field, the exchange bias (Hex), and the switching field distribution (SFD). Ho-doped NdFeO3 has an antiferromagnetic (AFM) character with an effective magnetic moment of 3.903 B.M. The UV–visible light absorbance of Nd0.90Ho0.10FeO3 is due to the transfer of electrons from the oxygen 2p state to the iron 3d state. Nd0.90Ho0.10FeO3 nanoparticles have an optical direct transition with an energy gap Eg = 1.106 eV. Ho-doped NdFeO3 can adsorb many heavy metals (Co2+, Ni2+, Pb2+, Cr6+, and Cd2+) from water. The removal efficiency is high for Pb2+ ions, which equals 72.39%. The Langmuir isotherm mode is the best-fit model for adsorbing the Pb2+ ions from water.

Improvement of the magnetic properties of Nd–Fe–B/glass two-layer films deposited on Si substrates

In a previous study, the authors developed Nd–Fe–B/glass two-layer films deposited on Si substrates using pulsed laser deposition for micro electro mechanical systems. Here, the fabrication conditions of the films were investigated to determine the optimum conditions that enhance the magnetic properties of the films. The annealing time in the pulse-annealing process conducted after the deposition was set to 4.0 s at Nd contents of 14 at.–16 at.%. Moreover, the effect of the glass/Nd–Fe–B thickness ratio on the magnetic properties was examined. A ratio less than 2 resulted in an increase in (BH)max up to 80 kJ/m3.

Study on electrical and magnetic properties of Nd–Co co-substituted M-type strontium ferrite suitable for microwave devices

Study on electrical and magnetic properties of Nd–Co co-substituted M-type strontium ferrite suitable for microwave devices

Microstructure and Magnetic Properties of Copper Mold Cast Nd–Fe–B Magnets Investigated by Phase‐Field and Micromagnetic Simulations

The effects of several factors, including alloy composition, cooling rate, and external magnetic field, on the microstructures and magnetic properties of Nd–Fe–B ternary alloy are explored in detail by using phase‐field and micromagnetic simulations during the copper mold casting process. It is found that the characteristic of regional distribution is formed due to the temperature gradient in the alloy, and that Nd19Fe71.5B9.5 (at%) exhibits the highest coercivity and pretty good comprehensive magnetic properties among all alloys studied, which can be interpreted by the refinement of Nd2Fe14B grain size and thickness of Nd‐rich grain boundary phase. The cooling rate has significant influence on the average grain size and the amount of amorphous phase. An increase of cooling rate results in a decrease of grain size and an increase of amorphous phase, which then affect the coercivity and remanence of the magnet. Applying an external magnetic field is demonstrated to be a good approach to enhance the coercivity and remanence by refining the grain size and restraining the formation of amorphous phase and T2 phase.

Structure, Composition and Magnetic Properties of Nd-(Fe,Co)-B Hard Magnetic Copper-Doped Powders

Structure, Composition and Magnetic Properties of Nd-(Fe,Co)-B Hard Magnetic Copper-Doped Powders

Structural aspects and magnetic properties of Nd3+ doped nickel-zinc ferrites

Magnetic properties and structural analysis of Nd(Neodymium) doped Ni0.65Zn0.35Fe2O4 using XRD, Rietveld Analysis, FTIR Spectroscopy and VSM are reported.Confirmation of secondary phase formation with increased Nd content is established. Cation distribution for neodymium substituted nickel-zinc ferritesis proposed by considering the deficiency of Fe3+ in NiZnFe2O4 due to secondary phase formation of NdFeO3. The quality of present cation distribution was confirmed through close agreement of experimentally calculated lattice constant and Rietveld refinement. Changes in saturation magnetization with increased Nd content are explained on the basis of intensifying effect on energy exchange (inter-sublattice) between Ni–O–Nd and Ni–O–Fe concnerning Fe–O–Fe interaction, effect of replacing lower magnetic moment Nd3+ (3.62 μB) in place of Fe3+ (5 μB) and exchange developed between the cations existing at B-sites due to creation of oxygen vacancies.

Microstructure, composition and magnetic properties of Nd-(Fe1-xCox)-B oxide magnetic particles synthesized by Pechini-type chemical method

This work deals with the investigation and optimization of the crystalline phases, magnetic properties, chemical composition and morphology of Nd-(Fe1-xCox)-B oxide magnetic particles (where x = 0, 0.05, 0.1, 0.15, 0.2, 0.3, 0.4, and 0.5) synthesized by Pechini method that can be used as a precursor for the production of Nd2(Fe,Co)14B hard magnetic phase. The polymerization mechanism of Pechini process was investigated by Fourier transform infrared (FTIR) and Raman spectroscopy to confirm the formation of metal-CA complexes and successive esterification reactions between citric acid (CA) and ethylene glycol (EG). The chemical composition of the synthesized samples was studied via energy dispersive (EDS) and X-ray photoelectro (XPS) spectroscopy methods. The structure, morphology, and the crystalline phase of resulting Nd-(Fe1-xCox)-B oxide magnetic particles were characterized by Rietveld refinement of X-ray diffraction (XRD) patterns, scanning electron microscopy ( SEM), and high-resolution transmission electron microscopy (HR-TEM) and its selected area electron diffractograms (SAED). The results obtained from the Rietveld refinement of XRD patterns show that (Fe2O3/Fe3O4) phase ratio decreases with the amount of cobalt that can be attributed to the reduction of enthalpy . The SEM micrographs indicate that the oxide particles have an elongated structure with irregular shapes supported by TEM observations. The results of structural analysis by HR-TEM and SAED are consistent with the Rietveld results which confirms the presence of different oxide phases in Nd-(Fe1-xCox)-B oxide particles. The magnetic behaviorstudied by VSM was interpreted by the variances of the morphology, structure and chemical composition of Nd-(Fe1-xCox)-B oxide particles, all of which were influenced by the cobalt content. First‐Order Reversal Curve (FORC) diagrams show that the magnetic interaction between oxide particles decreases as the cobalt content increases.

Phase formation and magnetic properties of (Nd1−xYx)14Fe80B6 melt-spun ribbons

Phase formation and magnetic properties of (Nd1−xYx)14Fe80B6 (x = 0.1–0.8) alloys were investigated experimentally by x-ray diffraction (XRD) and vibrating sample magnetometer (VSM). The phase structure analysis reveals that the as-cast (Nd1−xYx)14Fe80B6 alloys were made of 2:14:1 phase with tetragonal Nd2Fe14B-tpyed structure, REFe2 and α-Fe phases, while the melt-spun ribbons are composed of 2:14:1 phase and α-Fe Phase. Based on the magnetic measurements, the remanence (Br), the coercivity (Hcj), the maximum magnetic energy product ((BH)max) and the Curie temperatures (Tc) of (Nd1−xYx)14Fe80B6 ribbons reduces gradually with increasing Y substitution. The relatively high coercivity (6.75 kOe) of (Nd0.4Y0.6)14Fe80B6 ribbon with high Y substitution was achieved, which indicates that good magnetic properties of Nd–Y–Fe–B ribbons would be obtained through the design of alloy composition and phase formation.

Comparison of (Pr, Nd)H grain boundary restructuring and diffusion on the magnetic properties of Nd–La–Ce–Fe–B sintered magnet

Exploiting high-performance 2:14:1-type permanent magnet at high La–Ce substitution level remains a bottleneck concern due to the severe magnetic dilution from inferior intrinsic magnetism and microstructural deterioration. In present work, to promote the La–Ce application, (Pr, Nd)Hx is introduced into LaCe-40 sintered magnet (La–Ce/TRE = 40 wt%, TRE: total rare earth) through two approaches, grain boundary restructuring (GBR) and grain boundary diffusion process (GBDP). Results show that (Pr, Nd)Hx GBR leads to a twofold coercivity by optimizing the distribution of GB phase and forming a Pr/Nd-rich magnetically hardening shell. However, the remanence is lowered drastically due to massive formation of REFe2 phase during high-temperature sintering. Comparably, (Pr, Nd)Hx GBDP magnet with an identical average composition to GBR one yields a nearly threefold coercivity without sacrificing the remanence, ascribing to the formation of more continuous RE-rich GB layer and thicker Pr/Nd-rich shell near the surface region. Above comparative study highlights the crucial role of surface magnetic isolation in enhancing the coercivity of Nd–La–Ce–Fe–B sintered magnet, and delights the prospect of abundant La–Ce for industrial application.

Elemental analysis and the impact of Sr substitution on magnetic properties of Nd(1-x)Sr(x)MnO3 (x = 0; 0.5 and 1) perovskite manganite

The series sample of Nd(1-x)Sr(x)MnO3 (x = 0; 0.5 and 0.1) has been prepared with sol-gel method. The elemental compound or chemical characterization of Nd(1-x)Sr(x)MnO3 (x = 0; 0.5 and 0.1) were obtain using Energy Dispersive X-Ray Spectroscopy (EDS). The EDS results show that the elements were all presents in the sample, which also verified that the sample has successfully synthesized. The Vibrating Sample Magnetometer (VSM) was used to measure the magnetic properties of the sample under room temperature. The results show that the material is all soft magnetic with the magnetization decrease as the temperature decrease.

Effects of post-sinter annealing on microstructure and magnetic properties of Nd–Fe–B sintered magnets with Nd–Ga intergranular addition* *Project supported by the Major Project of Science and Technology Innovation 2025 in Ningbo, China (Grant No. 2018B10086), the Major Project of Inner Mongolia Science and Technology, Zhejiang Provincial Public Welfare Technology Application Research Project, China (Grant No. LGG21E010007), and the Key Research

We investigate the effects of post-sinter annealing on the microstructure and magnetic properties in B-lean Nd–Fe–B sintered magnets with different quantities of Nd–Ga intergranular additions. The magnet with fewer Nd–Ga additions can enhance 0.2 T in coercivity, with its remanences nearly unchanged after annealing. With the further increase of the Nd–Ga addition, the annealing process leads coercivity to increase 0.4 T, accompanied by a slight decrease of remanence. With the Nd–Ga addition further increasing and after annealing, however, the increase of coercivity is basically constant and the change of remanence is reduced. Microstructure observation indicates that the matrix grains are covered by continuous thin grain boundary phase in the magnets with an appropriate Nd–Ga concentration after the annealing process. However, the exceeding Nd–Ga addition brings out notable segregation of grain boundary phase, and prior formation of part RE 6Fe13Ga phase in the sintered magnet. This prior formation results in a weaker change of remanence after the annealing process. Therefore, the diverse changes of magnetic properties with different Nd–Ga concentrations are based on the respective evolution of grain boundary after the annealing process.

Unique magnetic properties of Nd based cuprate francisite: Major enhancement upon Co doping

To understand the physical mechanism of intralayer ferromagnetic (FM) and interlayer antiferromagnetic (AFM) interactions in quasi-two-dimensional model of a real three-dimensional system, rare earth (RE)-Nd based cuprate francisite, Cu3Nd(SeO3)2O2Cl (NdCufr) was doped with Co and studied using structural (X-ray diffraction technique), magnetic (temperature and field dependent magnetization and specific heat measurements) and local structural (X-ray absorption technique) techniques supported by first principle theoretical calculation. The structure of the samples is orthorhombic and doped specimens indicate more or less substitutional incorporation of Co at Cu site. The magnetic properties highlighted with two transitions, viz. AFM to paramagnetic (PM) transition around 30 K and a spin reorientation transition (SRT) below 10 K. Two phenomena viz. magnetic hysteresis below SRT and magnetic field induced metamagnetic transition (MMT) were observed. Co doping significantly enhanced these two phenomena in addition to change the transition temperatures. The concomitant change and enhancement of magnetic properties by Co doping has been interpreted using splitting scheme of Cu-d and Nd-f states. The local structure study corroborates the overall findings and detects the cause of unexpected trend of magnetism with increasing Co doping.

Enhancement in hard magnetic properties of (Nd, Pr)–Fe–B melt-spun ribbons

The coercivity of RE2Fe14B-type permanent magnets is strongly influenced by the microstructural features such as grain boundary (GB) phases as well as grain sizes. We have combined micromagnetic simulations and experiments to elucidate the role of excess RE (Nd/Pr) in determining the resulting hard magnetic properties of Nd–Pr–Fe–B melt-spun ribbons. The intrinsic coercivity (Hc) at room temperature significantly enhanced from 9.7 kOe to 15.3 kOe with the increase in the Nd/Pr content. Furthermore, the effect of non-magnetic grain refining refractory carbide (TiC) on both the microstructure and magnetic hardening was studied. The addition of TiC showed a very high coercivity Hc of up to 19.0 kOe at room temperature. Micromagnetic simulation indicates that the coercivity enhancement is mainly due to the reduction of inter-grain magnetic interaction, which is due to the RE-rich nonmagnetic grain boundary (GB) phase and/or TiC distributed at the GB. This work provides useful information on the roles of non-magnetic grain boundary phases for improving the coercivity of Nd–Pr–Fe–B magnets. Combined with experimental and modeling results, we have discussed the mechanism responsible for the enhancements in coercivity and the suitability of the alloys for high-performance permanent magnet development.

X-Ray Diffraction and Magnetic Properties of Nd Substituted NiZnFe2O4 Characterized by Rietveld Refinement

Solid-state method developed neodymium-doped Ni-Zn ferrites exhibit additional orthoferrite and α-Fe2O3 phases. The change in magnetic properties and lattice parameters are influenced by above mentioned extra phases other than the Nickel-Zinc ferrite spinel structure. Observations indicate that curie temperature, as well as saturation magnetization, reduce with an increase in Neodymium concentration. At the same time, for Nd = 0.02, initial permeability has been slightly increased. This paper explains the reason for these changes in terms of diluted octahedral sites replaced with Nd ions instead of Fe-ions and the number of additional phases that are present.

The effect of Tb4O7 powders addition on the magnetic properties for Nd–Fe–B sintered magnets with low rare earth content

The coercivity increased by 2.62 kOe with the formation Tb-rich shell by Tb diffusion after the dissolution of initial 0.5 wt% Tb4O7. With the increase of Tb4O7 additive amount, the increment of coercivity decreased first and then increased for Nd-Fe-B magnets. The dissolution of more Tb4O7 powder increased the Tb concentration gradient and promoted the diffusion of Tb into the inner area of grains. It resulted in the increase of the thickness of Tb-rich shell and the decrease of Tb efficiency. Increasing Tb4O7 addition beyond the O solubility in limited Nd-rich phase slowed down its dissolution. Thanks to the slow sustained release of Tb, Tb efficiency increased as the decrease of diffusion flux into the inner area of grains. The remaining (Nd,Tb,O)-rich phases can also enhance the coercivity.

Structure and Magnetic Properties of Nd0.88MnO3 Films Grown on SrTiO3 (100) Substrates by Liquid-Injection MOCVD

In this study, we investigated the structure and magnetic properties of Nd0.88MnO3 (NMO) perovskite thin-film layers by liquid-injection metalorganic chemical vapor deposition (MOCVD) tried on SrTiO3 (STO) (100) substrates. The structural examinations showed that the growing film was amorphous. It changed to the crystalline phase after being annealed at 900°C in air for 24 h. A minor secondary phase identified as Mn3O4 appeared. The film was subjected to in-plane (IP) tensile stress leading to a contraction of the film’s out-of-plane (OOP) lattice parameters. The orientation relationships for the film structure are described near the interface as $$ \left[ {10\bar{1}} \right] $$ NMO// $$ \left[ {100} \right] $$ STO and $$ \left[ {010} \right] $$ NMO// $$ \left[ {001} \right] $$ STO. The NMO thin film showed ferromagnetic ordering with a transition temperature TC = 85 K. The large bifurcation between ZFC and FC curves with a cusp at Tf = 53 K; and an irreversible temperature Tirr = 48 K proves that the spin-glass behavior with long-range ferromagnetic order (Mn3+-O2−-Mn4+) co-exists in NMO thin films. The magnetic easy axis corresponded to the surface normal.