Single Magnetic Domain Research Articles

Fabrication of Nd-Ho Cosubstituted Co0.5Ni0.5Fe2O4 Nanospinel Ferrites and Exploration of Their Microstructure, Magnetic, and Electromagnetic Characteristics.

The composition and hyperfine structures of Nd3+-Ho3+ ions cosubstituted CoNi nanospinel ferrites (Co0.5Ni0.5NdxHoxFe2-2xO4 (x ≤ 0.05) NSFs) as well as their magnetic and electrodynamic behavior have been presented. The compound Nd-Ho → CoNiFe2O4 (x ≤ 0.05) NSFs were produced using the sol-gel method. XRD powder patterns indicated phase- and substituent-induced modifications of crystallites. The SEM analysis indicated the homogeneous distribution of grains with Nd-Ho cosubstitution. It was found that the values of x had an impact on the hyperfine magnetic field of the A and B sites. The cation distribution was determined by using Mössbauer spectroscopy. The M-H loops' investigations showed that the current NSFs behave ferrimagnetically at both room and low temperatures. An almost continuous rise in the strength of the coercive field was noticed with a rise in Ho-Nd content. The value of calculated squareness ratio values was above 0.5 at both temperatures, entailing that the studied NSFs' structure is made of single magnetic domains. The electromagnetic characteristics of the samples can be explained by the main contribution to electromagnetic absorption being the electric energy losses. Electromagnetic absorbed materials can be applied to provide electromagnetic compatibility and develop functional electromagnetic shields.

Magnetosomes as Potential Nanocarriers for Cancer Treatment.

Magnetotactic bacteria (MTBs) and their organelles, magnetosomes, are intriguing options that might fulfill the criteria of using bacterial magnetosomes (BMs). The ferromagnetic crystals contained in BMs can condition the magnetotaxis of MTBs, which is common in water storage facilities. This review provides an overview of the feasibility of using MTBs and BMs as nanocarriers in cancer treatment. More evidence suggests that MTBs and BMs can be used as natural nanocarriers for conventional anticancer medicines, antibodies, vaccine DNA, and siRNA. In addition to improving the stability of chemotherapeutics, their usage as transporters opens the possibilities for the targeted delivery of single ligands or combinations of ligands to malignant tumors. Magnetosome magnetite crystals are different from chemically made magnetite nanoparticles (NPs) because they are strong single-magnetic domains that stay magnetized even at room temperature. They also have a narrow size range and a uniform crystal morphology. These chemical and physical properties are essential for their usage in biotechnology and nanomedicine. Bioremediation, cell separation, DNA or antigen regeneration, therapeutic agents, enzyme immobilization, magnetic hyperthermia, and contrast enhancement of magnetic resonance are just a few examples of the many uses for magnetite-producing MTB, magnetite magnetosomes, and magnetosome magnetite crystals. From 2004 to 2022, data mining of the Scopus and Web of Science databases showed that most research using magnetite from MTB was carried out for biological reasons, such as in magnetic hyperthermia and drug delivery.

Magnetic and structural enhanced characterization of Zr-Al substituted M-type barium hexaferrite

Co-precipitation method was used to fabricate Zr-Al substituted M-Type barium hexagonal ferrite with a unique composition Ba1-xZr0.5x Al0.3 Fe11.7 O19 (x = 0.0, 0.1, 0.2, 0.3, 0.4, and 0.5). The materials were characterized using Fourier Transform Infrared spectroscopy and a magnetic hysteresis loop. For each sample, the values of Ms, Hc, Mr, remanence ratios (Mr/Ms), and magneton number (nB) are determined using M-H loops. The Mr/Ms ratio of the synthesized hexaferrites particles is between 0.001017 and 0.143103, indicating a single magnetic domain. FTIR spectroscopy was used to study the inter-atomic forces and gives information about the absorption and emission spectrum for solids, liquids and gases. The results indicate that the synthesized compounds may have potential use as perpendicular magnetic recording media due to the growing trend in saturation magnetization, remanence, and coercivity.

Electric-Field Manipulation of Magnetic Chirality in a Homo-Ferro-Rotational Helimagnet.

Ferro-rotational (FR) materials, renowned for their distinctive material functionalities, present challenges in the growth of homo-FR crystals (i.e., single FR domain). This study explores a cost-effective approach to growing homo-FR helimagnetic RbFe(SO4)2 (RFSO) crystals by lowering the crystal growth temperature below the TFR threshold using the high-pressure hydrothermal method. Through polarized neutron diffraction experiments, it is observed that nearly 86% of RFSO crystals consist of a homo-FR domain. Notably, RFSO displays remarkable stability in the FR phase, with an exceptionally high TFR of ≈573K. Furthermore, RFSO exhibits a chiral helical magnetic structure with switchable ferroelectric polarization below 4K. Importantly, external electric fields can induce a single magnetic domain state and manipulate its magnetic chirality. The findings suggest that the search for new FR magnets with outstanding material properties should consider magnetic sulfates as promising candidates.

Micromagnetic simulation of the magnetization-controlled critical current in a S–(S/F)–S superconducting switch

In this Letter, we provide three dimensional micromagnetic simulations describing the nonvolatile magnetization control of the critical current of a superconductor–proximity-modified superconductor–superconductor junction by initializing and training its magnetization state in an external magnetic field, the experimental demonstration of which had been reported earlier. In the present work, we develop a microscopic explanation for the observed general behavior of the reduced critical current Ic in states of high magnetization M. We are able to reproduce the non-monotonous behavior of Ic(M) and can clearly correlate the discrete jumps in Ic(M) with flips of single or few magnetic domains in granular cobalt. We show that both the three-dimensional modeling and the grain size distribution are important to replicate the experimental observations.

Magnetic Tunability via Control of Crystallinity and Size in Polycrystalline Iron Oxide Nanoparticles.

Iron oxide nanoparticles (IONPs) arewidely used for biomedical applications due to their unique magnetic properties and biocompatibility. However, the controlled synthesis of IONPs with tunable particle sizes and crystallite/grain sizes to achieve desired magnetic functionalitiesacross single-domain and multi-domain size ranges remains an important challenge. Here, a facile synthetic method is used to produceiron oxide nanospheres (IONSs) with controllable size and crystallinity for magnetic tunability. First, highly crystalline Fe3O4 IONSs (crystallite sizes above 24nm) having an averagediameter of 50 to 400nm are synthesized with enhanced ferrimagnetic properties. The magnetic properties of these highly crystalline IONSs are comparable to those of their nanocube counterparts, whichtypically possess superior magnetic properties. Second, the crystallite size can be widely tuned from 37 to 10nm while maintaining the overall particle diameter, thereby allowing precise manipulation from the ferrimagnetic to the superparamagnetic state. In addition, demonstrations of reaction scale-up and the proposed growth mechanism of the IONSs are presented. This study highlights the pivotal role of crystal size in controlling the magnetic properties of IONSs and offers a viable means to produce IONSs with magnetic properties desirable for wider applications in sensors, electronics, energy, environmental remediation, and biomedicine.

Planar Hall Effect Magnetic Sensors with Extended Field Range.

The magnetic field range in which a magnetic sensor operates is an important consideration for many applications. Elliptical planar Hall effect (EPHE) sensors exhibit outstanding equivalent magnetic noise (EMN) on the order of pT/Hz, which makes them promising for many applications. Unfortunately, the current field range in which EPHE sensors with pT/Hz EMN can operate is sub-mT, which limits their potential use. Here, we fabricate EPHE sensors with an increased field range and measure their EMN. The larger field range is obtained by increasing the uniaxial shape-induced anisotropy parallel to the long axis of the ellipse. We present measurements of EPHE sensors with magnetic anisotropy which ranges between 12 Oe and 120 Oe and show that their EMN at 10 Hz changes from 800 pT/Hz to 56 nT/Hz. Furthermore, we show that the EPHE sensors behave effectively as single magnetic domains with negligible hysteresis. We discuss the potential use of EPHE sensors with extended field range and compare them with sensors that are widely used in such applications.

Engineering Plateau Phase Transition in Quantum Anomalous Hall Multilayers.

The plateau phase transition in quantum anomalous Hall (QAH) insulators corresponds to a quantum state wherein a single magnetic domain gives way to multiple domains and then reconverges back to a single magnetic domain. The layer structure of the sample provides an external knob for adjusting the Chern number C of the QAH insulators. Here, we employ molecular beam epitaxy to grow magnetic topological insulator multilayers and realize the magnetic field-driven plateau phase transition between two QAH states with odd Chern number change ΔC. We find that critical exponents extracted for the plateau phase transitions with ΔC = 1 and ΔC = 3 in QAH insulators are nearly identical. We construct a four-layer Chalker-Coddington network model to understand the consistent critical exponents for the plateau phase transitions with ΔC = 1 and ΔC = 3. This work will motivate further investigations into the critical behaviors of plateau phase transitions with different ΔC in QAH insulators.

Optimization of magnetic properties: Investigating the interaction of synthesis temperature, particle size, and monodomain formation in barium hexaferrite synthesized by the Pechini method

This study presents the synthesis and characterization of barium hexaferrite (BaFe12O19) powders via the Pechini method, employing controlled pH conditions (pH = 1) followed by sintering at temperatures ranging from 800 °C to 1150 °C. Structural and magnetic properties of the samples were investigated using various techniques, including Vibrating Sample Magnetometry, X-ray Diffractometry, and Scanning Electron Microscopy. Additionally,a theoretical analysis was conducted to determine the critical size required for achieving a single magnetic domain in the material. The results reveal a correlation between synthesis temperature and crystal size, ranging from 76 nm (at 800 °C) to 632 nm (at 1150 °C). Notably, samples sintered at 1050 °C exhibited exceptional magnetic properties, displaying a saturation magnetization (Ms) of 75.1 emu/g, a remanent magnetization (Mr) of 36.7 emu/g, and a coercivity (Hc) of 5.65 kOe. The particle size of these samples measured 327 nm, closely aligning with the critical diameter calculated for barium hexaferrite (378 nm) in this study. This optimal critical size was identified in sample sintered at 1050 °C, resulting in notably high coercivity values compared to those reported in previous literature. These findings highlight the significance of synthesis temperature control in tailoring the magnetic properties of barium hexaferrite, offering insights into optimizing its performance for various applications.

Effect of lightly substituted samarium ions on the structural, optical, magnetic and dielectric properties of the sonochemically synthesized M-type Sr-hexaferrite nanoparticles

In this study, the role of sonochemical treatment followed by a combustion process adopted for the synthesis of SrSmxFe12-xO19 (x = 0.01 to 0.03) hexaferrites. We have investigated effect of lightly Sm substitutions on structural, magnetic, optical and dielectric properties in Strontium hexaferrites. X-ray diffraction analysis show M as major phase with impurity. The FTIR analysis shows that the value of force constant increased on both sides (tetra hederal and octa hederal) with the increase of samarium content. The band gap was calculated using Tauc method from UV–Visible spectra. Result shows that as the samarium content increases from x = 0.01 to 0.03 the band gap gradually increases from 2.50 eV 2.91 eV respectively. The surface morphology of prepared Sm substituted SrM nanoparticles was examined using field emission scanning electron microscopy, an average particle size was found to 301 nm, 254 nm, and 285 nm for x = 0.01, 0.02, and 0.03 compositions respectively. High values of Ms (53.104 emu/g.) and Mr (29.0 emu/g) observed in x = 0.03 sample with low Hc of 53.104 Oe. Mr/Ms values of all samples are >0.5 show that of formed hexaferrite nanoparticles possess single magnetic domain structure. The Sm-doped of the SrFe12O19 compound exhibits a low dielectric constant (ε′) ∼ 20 at low frequencies, while it increased with increasing temperature and reached 100 when the Sm content was 0.01, but less than 150 in x = 0.02 and 0.03. The temperature and frequency-dependent dielectric constant confirmed the contributions of different polarization mechanisms.

A systematic study of oxygen vacancy mediated short range and long range magnetic ordering in BaTi1-xFexO3(x = 0.02)

A systematic study on the magnetic properties of the BaTi1-xFexO3-δ (x = 0.02) system with decrease in grain sizes is presented. The combined study of long range and short range magnetic orderings together was carried out. The samples were prepared in single tetragonal phase. The grains of the pristine sample were refined from micron to nanometer range by mechanical milling. Oxygen vacancies in different charge states gave rise to ferromagnetic and antiferromagnetic orderings among the Fe3+ ions whereas oxygen atoms acted as the medium for antiferromagnetic superexchange among the Fe3+ ions. Magnetization was found to increase significantly as a result of milling and eventually the saturation magnetization became four-fold in the sample with grain size around 18 nm. The increase in magnetization is attributed to the increase in oxygen vacancies as a consequence of increase in milling time. Clear sextet patterns in the Mössbauer spectra were observed in the sample wherein 57Fe–enriched iron was used in place of natural iron. These sextets were attributed to the presence of FM and AFM orderings among Fe3+ ions. Along with the sextet patters, we also observed a doublet pattern in Mössbauer spectra because of quadrupolar interaction of the isolated Fe3+ ions arranged in non-cubic environment and lacking any kind of magnetic interactions among them. Mössbauer Spectroscopic (MS) study revealed that FM ordering increased while AFM ordering disappeared after milling. Drastic fall of coercivity in samples with grain sizes below around 40 nm indicated that they became single magnetic domain.

Investigating the magnetic domain structure and photonics characters of Singled Phased hard ferromagnetic Ferrite MFe3O4 (M= Co2+, Zn2+, Cd2+) Compounds

The impact of transition metals on ferrite (iron (III) oxide) compounds is investigated in this study. Ferrite samples were synthesized using the co-precipitation method. X-ray analysis unveiled the presence of the Fe-phase in the trivalent state, showcasing a single-phased cubic spinel framework with a preferred orientation along the (311) reflection plane. Crystallite sizes were determined for CdFe3O4, ZnFe3O4, and CoFe3O4 utilizing the Scherer equation, yielding values of 10.54 nm, 18.76 nm, and 32.63 nm, respectively. Zinc ferrite displayed an intermediate photonic nature compared to cobalt and cadmium ferrite, with cadmium ferrite showing high optical losses and cobalt ferrite exhibiting minimal optical losses. EDX analysis confirmed the presence of Zn2+, Co2+, Fe3+, Cd2+, and O2? ions in the correct ratios, supporting the intended stoichiometric composition. Optical assessment revealed that CoFe3O4 nanoparticles are well-suited for optoelectronic devices, ultraviolet detectors, and infrared (IR) detectors. VSM measurements of cobalt ferrite exhibited higher coercivity and magnetic saturation compared to other samples. Photoluminescence (PL) spectroscopy revealed multiple colors, including cyan, green, and yellow, at different wavelengths for the ferrite samples. These findings suggest that the synthesized samples are suitable materials for high-frequency devices owing to their robust magnetic properties. Cadmium ferrite displayed a multi-magnetic domain structure, contrasting with the single-magnetic domain structure observed in zinc and cobalt ferrite.

Magnetic Mesoporous Silica for Targeted Drug Delivery of Chloroquine: Synthesis, Characterization, and In Vitro Evaluation.

Malaria is a dangerous tropical disease, with high morbidity in developing countries. The responsible parasite has developed resistance to the existing drugs; therefore, new drug delivery systems are being studied to increase efficacy by targeting hemozoin, a parasite paramagnetic metabolite. Herein, magnetic mesoporous silica (magMCM) was synthesized using iron oxide particles dispersed in the silica structure for magnetically driven behavior. The X-ray diffractogram (XRD) and Mössbauer spectra show patterns corresponding to magnetite and maghemite. Furthermore, Mössbauer spectroscopy revealed superparamagnetic behavior, attributed to single magnetic domains in particles smaller than 10 nm. Even in the presence of iron oxide particles, the hexagonal structure of MCM is clearly identified in XRD (low-angle region) and the channels are visible in TEM images. The drug chloroquine (CQ) was encapsulated by incipient wetness impregnation (magMCM-CQ). The N2 adsorption-desorption isotherms show that CQ molecules were encapsulated in the pores, without completely filling the mesopores. BET surface area values were 630 m2 g-1 (magMCM) and 467 m2 g-1 (magMCM-CQ). Encapsulated CQ exhibited rapid delivery (99% in 3 h) in buffer medium and improved solubility compared to the non-encapsulated drug, attributed to CQ encapsulation in amorphous form. The biocompatibility assessment of magMCM, magMCM-CQ, and CQ against MRC5 non-tumoral lung fibroblasts using the MTT assay after 24 h revealed no toxicity associated with magMCM. On the other hand, the non-encapsulated CQ and magMCM-CQ exhibited comparable dose-response activity, indicating a similar cytotoxic effect.

Incremental Analysis of Magnetic Domains in Multiple Types of Ferromagnetic CoFe Nanolayer Patterns

In this article, the results of incremental analysis on the thickness, aspect ratio, and crystallographic substrate orientation dependence of magnetic domain formation in CoFe nanolayer patterns (NPs) on GaAs (001) substrates by magnetic force microscopy are reported. All the 35 nm thick CoFe NPs show multiple magnetic domains under as‐deposition condition whereas the 13 nm thick CoFe NPs have a single magnetic domain in the case of the patterns with a relatively small size and high aspect ratio. Subsequently, the magnetic fields are applied in the direction parallel to the <110> and <1–10> directions of the substrates to analyze a magnetization switching behavior in the patterns. The results reveal that the magnetic fields required for magnetization switching markedly tend to increase, with decreasing the thickness of the patterns and increasing their aspect ratio. A general tendency is obtained, which a higher magnetic field is needed for a higher aspect ratio and a thinner thickness of the NPs. Even in the case of the patterns with an aspect ratio of unity and a thickness of 35 nm (but, a smaller size), a single magnetic domain is formed at a relatively high applied magnetic field of 1500 Gauss.

On the sign of the linear magnetoelectric coefficient in Cr2O3

We establish the sign of the linear magnetoelectric (ME) coefficient, α, in chromia, Cr2O3. Cr2O3 is the prototypical linear ME material, in which an electric (magnetic) field induces a linearly proportional magnetization (polarization), and a single magnetic domain can be selected by annealing in combined magnetic (H) and electric (E) fields. Opposite antiferromagnetic (AFM) domains have opposite ME responses, and which AFM domain corresponds to which sign of response has previously been unclear. We use density functional theory (DFT) to calculate the magnetic response of a single AFM domain of Cr2O3 to an applied in-plane electric field at zero kelvin. We find that the domain with nearest neighbor magnetic moments oriented away from (towards) each other has a negative (positive) in-plane ME coefficient, α⊥ , at zero kelvin. We show that this sign is consistent with all other DFT calculations in the literature that specified the domain orientation, independent of the choice of DFT code or functional, the method used to apply the field, and whether the direct (magnetic field) or inverse (electric field) ME response was calculated. Next, we reanalyze our previously published spherical neutron polarimetry data to determine the AFM domain produced by annealing in combined E and H fields oriented along the crystallographic symmetry axis at room temperature. We find that the AFM domain with nearest-neighbor magnetic moments oriented away from (towards) each other is produced by annealing in (anti-)parallel E and H fields, corresponding to a positive (negative) axial ME coefficient, α∥ , at room temperature. Since α⊥ at zero kelvin and α∥ at room temperature are known to be of opposite sign, our computational and experimental results are consistent.

Magnetic-Field-Assisted Electric-Field-Induced Domain Switching of a Magnetic Single Domain in a Multiferroic/Magnetoelectric Ni Nanochevron/[Pb(Mg1/3Nb2/3)O3]0.68-[PbTiO3]0.32 (PMN-PT) Layered Structure.

We report the magnetic-field-assisted electric-field-controlled domain switching of a magnetic single domain in a multiferroic/magnetoelectric Ni nanochevrons/[Pb(Mg1/3Nb2/3)O3]0.68-[PbTiO3]0.32 (PMN-PT) layered structure. Initially, a magnetic field was applied in the transverse direction across single-domain Ni nanochevrons to transform each of them into a two-domain state. Subsequently, an electric field was applied to the layered structure, exerting the converse magnetoelectric effect to transform/release the two-domain Ni nanochevrons into one of two possible single-domain states. Finally, the experimental results showed that approximately 50% of the single-domain Ni nanochevrons were switched permanently after applying our approach (i.e., the magnetization direction was permanently rotated by 180 degrees). These results mark important advancements for future nanoelectromagnetic systems.

Highly ordered single domain Fe2-xCo1+xGa (0 ≤ x ≤ 1) nanoparticles synthesized by a template-less chemical route

A comprehensive study has been carried out on chemically synthesized Fe2-xCo1+xGa (0 ≤ x ≤ 1) nanoparticles using both experimental and theoretical tools. Adoption of a template-free preparation route ensured impurity-free and phase-pure Heusler alloy nanoparticles. Depending on the composition, these nanoparticles exhibit highly ordered L21 or X type Heusler alloy structure. These nanoparticles have high saturation magnetization (3.90 – 5.15 µB/f.u.), high Curie temperature (≥ 1100 K) and high effective anisotropy constant (∼ 106 erg/cc) along with low coercive field (≤ 12 Oe) and low remnant magnetization (≤ 0.03 µB/f.u.). Emergence of superparamagnetism in these single (magnetic) domain nanoparticles is another interesting aspect. The electronic density of states of these alloys near Fermi level have also been evaluated as a function of composition using ab initio calculations. These results indicate Fe2-xCo1+xGa nanoparticles to be promising candidates for high density magnetic media and nanomagnetic sensor applications.

Effect of La3+/Cu2+ and La3/Ni2+ substitution on the synthesis, magnetic and dielectric properties of M−type Sr1-xLaxFe12-xMxO19 (M = Cu and Ni) hexaferrite

Here, we report a comprehensive study to explore the synthesis and comparative analysis of co-substituted M−type La3+/Cu2+ and La3+/Ni2+ hexaferrite (Sr1-xLaxFe12-xMxO19 where M = Cu and Ni; (x = 0.0, 0.05, 0.1, 0.15, and 0.2)) prepared through the sol–gel auto-combustion approach. X-ray diffraction (XRD) analysis shows both systems' single-phase structure of Sr hexaferrite. The structural parameters decreased as the number of substituted ions increasedas the crystal lattice contracts due to the smaller ionic radii being doped. Theaverage crystallite sizes were found using the Scherrer equation using the highest intensity peaks, and the results show nano-sized particles. The morphological structure of Sr-hexaferrite was studied using Field Effect Scanning Microscopy (FESEM). As a result, irregularly shaped particles with slight agglomeration are observed on the topography in both systems. Two absorption bands were observed in all synthesised samples' Fourier-transformed infrared spectroscopy (FTIR) spectra, supporting the ferrite's formation. These materials are a good option for high-density recording media. Both samples show high magnetic natures, which can be observed from the hysteresis loop. Overall, the room temperature magnetic parameters measured slightly increase as the dopant materials increase. The squareness ratio of the synthesizedsamples shows the uniaxial anisotropy with single magnetic domain particles. The Maxwell-Wagner and Koop model clarifies the reason the dielectric characteristics exhibit the typical behavior of ferrites.

Quantitative magnetization measurements of magnetic particles with FePt standard samples

Micrometer-sized magnetic particles have been widely used in magnetic force microscopy, magnetic resonance force microscopy, and bio-sensing. To quantitatively interpret the data obtained with magnetic particles, it is important to know the magnetic properties of the particles. However, the magnetic moment of individual particle is usually too small to be measured by common instruments for samples with large volume. Here, we present a method to characterize magnetic microspheres using patterned FePt thin films as standard samples. The FePt thin film in the L10 phase has perpendicular magnetic anisotropy, and the patterned features can be magnetized to near single-domain magnets, which make them suitable standards for magnetic sphere calibration with magnetic force microscopy. Multiple linear regression is used to analyze the frequency shift images and obtain the effective dipole moment of the spheres. The position of the dipole moment is obtained by minimizing the residuals in multiple linear regression with a gradient descent algorithm. Three NdFeB spheres of different diameters were measured. It was found that the magnetization increases with the increase in the diameter of the sphere, possibly due to the weakening of ferromagnetism on the surface.

Synthesis and physical properties of pure NiO and Ni1–2xMgxMxO (M= Cu, Ru) nanoparticles: Role of growth temperature

Herein, low-cost chloride precursors, EDTA, and NaOH were employed through a facile coprecipitation synthesis route to prepare pure and codoped NiO nanoparticles: Ni1–2xMgxMxO, where M = Cu and Ru and x = 1, 4, and 8 at%. To examine the impact of reaction temperature on the thermal, structural, morphological, optical, and magnetic properties of the prepared samples, the precursor aqueous solutions were heated at 60, 70, and 80 ºC. Data analysis revealed the strong dependence of all the studied properties on reaction temperature and codoping. Thermogravimetric analysis (TGA) was performed to evaluate the thermal stability of the prepared samples. The face-centered cubic (fcc) crystallization of NiO was maintained at all the applied temperatures and doping concentrations. X-ray diffraction (XRD) patterns showed the good incorporation of Mg2+ and Cu2+ ions with the host Ni2+ ions in Ni1–2xMgxCuxO samples, while peaks of RuO2 appeared as an impurity phase in Ni1–2xMgxRuxO samples. Tiny spherical nanoparticles with a crystallite size of 6 nm were produced at 80 ºC and 8 at% (Mg, Ru) codoping. Energy dispersive X-ray (EDX) analysis confirmed that the elemental compositions of the synthesized samples were in stoichiometric ratios. The UV-Vis spectra demonstrated a monotonic increase in band gap with reaction temperature and codoping. The estimated Herve-Vandamme refractive index (nHV), the high (ε∞) and the static (εo) dielectric constants showed a decreasing trend with increasing reaction temperature. Weak ferromagnetic behavior was observed for the pure NiO samples, while the codoped samples with x > 4% showed linear M-H curves. The coercivety (Hc) decreased with reaction temperature, implying single-domain magnetization and sizes below the critical one. The magnetocrystalline anisotropy (K) indicated the softness of the prepared samples.