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The core and surface structure, and magnetism of mechano-synthesized LaFeO3 nanoparticles (30–40 nm), Eu3+-doped (La0.70Eu0.30FeO3), and Eu3+/Cr3+ co-doped (La0.70Eu0.30Fe0.95Cr0.05O3) are reported. Doping results in a transition from the O′-type to the O-type distorted structure. Traces of reactants, intermediate phases, and a small amount of Eu2+ ions were detected on the surfaces of the nanoparticles. The nanoparticles consist of antiferromagnetic cores flanked by ferromagnetic shells. The Eu3+ dopant ions enhance the magnetization values relative to those of the pristine nanoparticles and result in magnetic susceptibilities compatible with the presence of Eu3+ van Vleck paramagnetism of spin–orbit coupling constant (λ = 363 cm−1) and a low temperature Curie–Weiss like behavior associated with the minority Eu2+ ions. Anomalous temperature-dependent magnetic hardening due to competing magnetic anisotropy and magnetoelectric coupling effects together with a temperature-dependent dopant-sensitive exchange bias, caused by thermally activated spin reversals at the core of the nanoparticles, were observed. [ABSTRACT FROM AUTHOR]

This study aimed to develop multifunctional nanoplatforms for both cancer imaging and therapy using superparamagnetic iron oxide nanoparticles (SPIONs). Two distinct synthetic methods, reduction–precipitation (MR/P) and co-precipitation at controlled pH (MpH), were explored, including the assessment of the coating's influence, namely dextran and gold, on their magnetic properties. These SPIONs were further functionalized with gadolinium to act as dual T1/T2 contrast agents for magnetic resonance imaging (MRI). Parameters such as size, stability, morphology, and magnetic behavior were evaluated by a detailed characterization analysis. To assess their efficacy in imaging and therapy, relaxivity and hyperthermia experiments were performed, respectively. The results revealed that both synthetic methods lead to SPIONs with similar average size, 9 nm. Mössbauer spectroscopy indicated that samples obtained from MR/P consist of approximately 11–13% of Fe present in magnetite, while samples obtained from MpH have higher contents of 33–45%. Despite coating and functionalization, all samples exhibited superparamagnetic behavior at room temperature. Hyperthermia experiments showed increased SAR values with higher magnetic field intensity and frequency. Moreover, the relaxivity studies suggested potential dual T1/T2 contrast agent capabilities for the coated SPpH-Dx-Au-Gd sample, thus demonstrating its potential in cancer diagnosis. [ABSTRACT FROM AUTHOR]

Herein, the synthesis of Co2Si5N8 nitridosilicate from α‐Ca2Si5N8 by ion exchange is described. The monoclinic Co2Si5N8$\left(\text{Co}\right)_{2} \left(\text{Si}\right)_{5} \left(\text{N}\right)_{8}$ structure (space group Cc) is compared with those of the related nitridosilicates Ca2Si5N8 and Fe2Si5N8 its magnetic properties are profoundly investigated. Most interestingly, polycrystalline Co2Si5N8 exhibits a quasi‐temperature‐independent paramagnetic susceptibility of about 6×10−3 cm3 mol−1$>$$ 6\times {10}^{-3} {\text{cm}}^{3} {\text{mol}}^{-1}$$ over a wide temperature range from 100 to 600 K. Two different magnetic models based on a phenomenological Hamiltonian that takes into account magnetic exchange coupling, crystal‐field interactions, and Zeeman effects within the framework of an angular momentum basis set are refined to the experimental susceptibility datasets. The results of the refinements point to the realization of a pseudo temperature independent paramagnetism for Co2Si5N8 that results from a near‐perfect cancellation of temperature‐dependent contributions to the susceptibility depending delicately on the mixing of ion levels in the electronic states, their relative energies, and the magnetic coupling between them. Additionally, performed direct current field scan, alternating current susceptibility, and heat capacity measurements complete the magnetic characterization and facilitate the identification of impurity phase contributions. [ABSTRACT FROM AUTHOR]

This work presents a comprehensive analysis of the magnetic properties of pristine and citric acid-coated cobalt ferrite (${\rm{CoF}}{{\rm{e}}_{\rm{2}}}{{\rm{O}}_{\rm{4}}}$ CoF e 2 O 4 ) nanoparticles (NPs) dispersed in the host nematic $4{^{\prime}}$ 4 ′ -heptyl-4-biphenylcarbonnitrile (7CB) system. Our results shed light on the promising potential of combining liquid crystals (LC) with magnetic nanoparticles for cancer treatment. This opens up exciting avenues for further exploration and possible applications in the field of oncology. The study focuses on examining the magnetic behaviour of LC dispersed systems with two concentrations of magnetic nanoparticles (0.03 and 0.04 wt%). Notably, intriguing temperature-dependent magnetisation plots reveal a distinctive cusp, which can be attributed to the freezing phenomenon of the liquid crystal. This observation offers valuable insights into the system's magnetic properties and interactions, deepening our understanding of its behavior. [ABSTRACT FROM AUTHOR]

Present work focuses to investigate the impact of rare earth ions (Ce and Gd) on the structural and magnetic properties of nanocrystalline nickel-zinc ferrite. The nanoparticles of Ni0.5Zn0.5Fe2O4, Ni0.5Zn0.5Ce0.02Fe1.98O4, and Ni0.5Zn0.5Gd0.02Fe1.98O4 were synthesized by citric acid–assisted sol–gel method. The formation of cubic spinel structure without additional impurity peaks was confirmed by X-ray diffraction (XRD) pattern. The crystallite size of Ni0.5Zn0.5Fe2O4 (R = 0) and Ni0.5Zn0.5R0.02Fe1.98O4 (R = Ce and Gd) nanoparticles was observed less than ~ 35 nm at sintering temperatures of ~ 300 to ~ 500 ℃. From magnetic measurements, the value of room temperature saturation magnetization of superparamagnetic Ni0.5Zn0.5Fe2O4 (R = 0) was found to be reduced with the doping of Ce and Gd ions from 44.19 ± 0.02 to 39.33 ± 0.03 emu/g and 35.18 ± 0.02 emu/g, respectively, at 300 ℃ and from 60.69 ± 0.04 to 54.11 ± 0.03 emu/g and 55.72 ± 0.04 emu/g, respectively, at 500 ℃. The detailed study of superparamagnetic relaxation in pure and rare earth-doped samples was performed by the thermal magnetization measurements under zero field cool (ZFC) and field cool (FC) processes. Mossbauer spectra revealed the absence of the quadrupole splitting for Ni0.5Zn0.5Ce0.02Fe1.98O4 at tetrahedral (A-site) and octahedral (B-site) sites which indicated cubic symmetry in the crystal structure. Although, the presence of negative asymmetry was observed in Ni0.5Zn0.5Gd0.02Fe1.98O4-doped ferrite sample. Magnetic materials with superparamagnetic properties are desirable in various biomedical applications. [ABSTRACT FROM AUTHOR]

A series of La3+ ion doped magnesium nickel ferrites, Mg 0.5 Ni 0.5 Fe 2-x La x O 4 (0 ≤ x ≤ 0.1) having a cubic spinel structure were prepared by the co-precipitation method. Various characterization techniques, including X-ray diffractometer (XRD), high resolution transmission electron microscopy (HR-TEM), electron spin resonance (ESR) and vibrating sample magnetometer (VSM) were used to investigate structural and magnetic properties. The average crystallite size decreases and lattice parameter increases with La3+ ion doping and lie in the range of 12–7 nm and 8.347–8.361 Å respectively. Analysis of ESR spectra reveals that, g-value with La3+ ion addition decreases from 2.57 to 2.12. The saturation magnetization and the coercivity decrease with increasing rare-earth content. Magnetic-hysteresis (M − H) loop shifts from a ferromagnetic to a superparamagnetic nature with La3+ ion addition. The dielectric study was carried out in the frequency range of 1 KHz to 4000 KHz and temperature ranging 30 °C–350 °C using the impedance analyzer. The dielectric constant decreases with increasing frequency and the La3+ ion concentration. The dielectric loss of the sample increases with increasing temperature. The magnetic properties of the synthesized nanoparticles make them a potential material for stable ferrofluid application and the low tangent loss value makes these material a potential candidate for frequency-based applications. [ABSTRACT FROM AUTHOR]

The AC magnetic properties of a sample of Fe3O4 nanoparticles coated with oleic acid have been investigated with the help of AC susceptibility measurements. In particular, several DC magnetic fields have been superimposed on the AC field, and their effect on the magnetic response of the sample has been analysed. The results show the presence of a double peak structure in the imaginary component of the complex AC susceptibility measured as a function of the temperature. A preliminary evaluation of the Mydosh parameter for both peaks gives the information that each one of them is associated with a different state of interaction between nanoparticles. The two peaks evolve both in amplitude and position when the intensity of the DC field is changed. The field dependence of the peak position shows two different trends, and it is possible to study them in the framework of the currently existing theoretical models. In particular, a model of non-interacting magnetic nanoparticles has been used to describe the behaviour of the peak at lower temperatures, whereas the behaviour of the peak at higher temperatures has been analysed in the framework of a spin-glass-like model. The proposed analysis technique can be useful for the characterisation of magnetic nanoparticles used in several types of applications, such as biomedical and magnetic fluids. [ABSTRACT FROM AUTHOR]

A series of polynuclear Cu(II) complexes, namely, (Him)2[Cu2(pzdc)2(H2O)2] (1), [Cu3(pzdc)2(im)2(H2O)4] (2), {[Na4Cu4(pzdc)4(im)4(H2O)2]·16H2O}n (3), (Hamp)2[Cu2(pzdc)2(H2O)2] (4), (H2tmdp)2[Cu4(pzdc)4(H2O)2]·2H2O (5), {[Cu2(pzdc)2][Cu(H2O)6]}n (6), and [Cu3(pzdc)2(en)2(H2O)2]n (7), were successfully synthesized under the reaction of Cu(NO3)2·3H2O, pyrazole-3,5-dicarboxylic acid, and various ancillary ligands (im = imidazole, amp = 4-aminopyridine, tmdp = 4,4′-trimethylenedipyridine, and en= ethylenediamine). The magnetic study based on the secondary building Cu(II) unit with pyrazole-3,5-dicarboxylate bridges can be divided into three groups: (Group I) dinuclear Cu(II) units of 1, 4, and 6, (Group II) trinuclear Cu(II) units of 2 and 7, and (Group III) tetranuclear Cu(II) units of 3 and 5. The magnetic properties of 1 and 4 (group I) exhibit spin-canted antiferromagnetism while 6 exhibits typical antiferromagnetic coupling within the Cu(II) dimer with the paramagnetism from the [Cu(H2O)6]2+ unit. Group II exhibits antiferromagnetic interactions within the Cu(II) trimer for 2 and 7. Group III displays antiferromagnetic and weak ferromagnetic interactions within the tetranuclear Cu(II) unit. [ABSTRACT FROM AUTHOR]

Superparamagnetic iron oxide nanoparticles (SPIONs) coated with the synthetic hydrophilic biocompatible polymer polyvinyl alcohol were synthesized using the aqueous method. Static and dynamic magnetization processes were investigated for surface-modified SPIONs by analyzing the magnetization study at constant and varying magnetic fields. The magnetization on the applied magnetic field (M–H) and the magnetization dependent on temperature (M–T) were investigated. The temperature dependence of the complex susceptibility of SPIONs was investigated by measuring the in-phase (natural) and out-of-phase (imaginary) components of the susceptibility value at a frequency of 10 Hz and a very low magnetizing field. The XRD study shows diffraction peaks consistent with the magnetite (Fe3O4) phase of SPIONPs. FTIR, DSC, and TGA studies confirm the functional groups and stability of the coated nanoparticles. The magnetizing field cycle study at various constant temperatures (10, 100, and 300 K) shows the high magnetization value of polyvinyl alcohol-coated SPIONs with superparamagnetic states at and above 300 K. The effect of interparticle interaction on blocking temperature has been interpreted from FC/ZFC curves drawn at different DC magnetizing field values by varying temperature between 10 and 300 K. [ABSTRACT FROM AUTHOR]

Sr-doped (0

Late diagnosis and systemic toxicity associated with conventional treatments make oncological therapy significantly difficult. In this context, nanomedicine emerges as a new approach in the prevention, diagnosis and treatment of cancer. In this work, pH-sensitive solid magnetoliposomes (SMLs) were developed for controlled release of the chemotherapeutic drug doxorubicin (DOX). Shape anisotropic magnetic nanoparticles of magnesium ferrite with partial substitution by calcium (Mg0.75Ca0.25Fe2O4) were synthesized, with and without calcination, and their structural, morphological and magnetic properties were investigated. Their superparamagnetic properties were evaluated and heating capabilities proven, either by exposure to an alternating magnetic field (AMF) (magnetic hyperthermia) or by irradiation with near-infrared (NIR) light (photothermia). The Mg0.75Ca0.25Fe2O4 calcined nanoparticles were selected to integrate the SMLs, surrounded by a lipid bilayer of DOPE:Ch:CHEMS (45:45:10). DOX was encapsulated in the nanosystems with an efficiency above 98%. DOX release assays showed a much more efficient release of the drug at pH = 5 compared to the release kinetics at physiological pH. By subjecting tumor cells to DOX-loaded SMLs, cell viability was significantly reduced, confirming that they can release the encapsulated drug. These results point to the development of efficient pH-sensitive nanocarriers, suitable for a synergistic action in cancer therapy with magnetic targeting, stimulus-controlled drug delivery and dual hyperthermia (magnetic and plasmonic) therapy. [ABSTRACT FROM AUTHOR]

NdFe1−xCoxO3 samples are prepared by the sol–gel method. The X‐ray diffraction (XRD) results show that these samples conform to the orthogonal perovskite structure (Pbnm), and different doping amounts can cause the patterns to shift by XRD pattern. Through the Williamson–Hall analysis, the microstrain of the lattice between different doping amounts was obtained, and the average crystal size was calculated. The element content of each sample was obtained by scanning electron microscope and energy‐dispersive X‐ray analysis. Mössbauer spectra show that different doping levels change the surrounding environment of iron, and the magnetic properties of the samples also change. [ABSTRACT FROM AUTHOR]

Lanthanum doped magnesium-zinc spinel ferrite samples were synthesized by the simple co-precipitation method with composition M g 0.5 Z n 0.5 F e 2 − x L a x O 4 (x = 0,0.025,0.05,0.075 a n d 0.1). The synthesized ferrite samples were investigated using by powder X-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FTIR), Field emission scanning electron microscopy (FE-SEM) coupled with energy dispersive spectroscopy (EDS), high resolution transmission electron microscopy (HR-TEM), electron paramagnetic resonance spectroscopy (EPR) and vibrating sample magnetometer (VSM). The effect of the La3+ ion doping on the crystallite size and lattice parameter of the material has been discussed. The crystallite size for all the samples were found to be in the range of 7–12 nm. The percentage porosity and percentage crystallinity of all the samples were found to be in the range of 49–50% and 80–85% respectively. In the frequency region of 400–600 cm−1 two absorption bands attributed to the T d and O h sites of the spinel ferrite have been observed. FTIR band spectra shift from lower to higher region with La3+ ion doping. Agglomeration of the particles is observed in the FE-SEM and HR-TEM images. Additional impurities except carbon are not present in the sample which is confirmed by EDS analysis. EPR analysis shows a decrease in the g-value from 2.18 to 2.12 for the synthesized samples with La3+ ion doping. The resonance field for synthesized sample shifts to higher magnetic field which may be due to ferromagnetic interaction caused by La3+ ion doping. The maximum spin concentration (1.508 × 1021 spin/g) and the relaxation time (4.132 × 10−11 s−1) was observed for the MZL2 composition. Magnetization curve shows the typical superparamagnetic nature of synthesized samples. The calculated squareness value of the synthesized sample refers to the magnetostatic interaction among particles. The obtained coercive field value is low which makes these materials suitable for ferrofluids and hyperthermia treatment applications. [ABSTRACT FROM AUTHOR]

Two unique spinel compounds of type NiRh2S4 and RhNi2S4 crystal structure with chemical formula AB2X4 (A = Ni, Rh; B = Rh, Ni; and X = S) are chosen for the first time due to their importance in catalyst reactions and interesting physical properties to explore their structural, mechanical, electronic, and magnetic properties. First principle treatment has been implemented for the above-mentioned compounds with full potential linearized augmented plane wave plus local orbital methods (FPLAPW + LO) within the exchange correlation potentials range of state of the art density functional theory (DFT). The results obtained for the structural properties of these compounds using GGA approximation are compared with already available experimental results in the literature. Our spotted lattice constants for NiRh2S4 and RhNi2S4 are found to be consistent with experiment. Additionally we have also implemented the GGA + U potential for the improvements of electronic and magnetic characteristics of the compounds under investigation. Centered on the magneto-electronic properties, these compounds are metallic and paramagnetic in nature. Moreover, the crystal field splitting and the elastic properties of NiRh2S4 and RhNi2S4 are also discovered. The studies reveal that these compounds are elastically stable and ductile in character. Metallic characteristics and paramagnetic behavior of the compounds under observation predict their importance in spintronic and acoustical devices. [ABSTRACT FROM AUTHOR]

Superparamagnetic nanoparticles are of high interest for therapeutic applications. In this work, nanoparticles of calcium-doped manganese ferrites (CaxMn1−xFe2O4) functionalized with citrate were synthesized through thermally assisted oxidative precipitation in aqueous media. The method provided well dispersed aqueous suspensions of nanoparticles through a one-pot synthesis, in which the temperature and Ca/Mn ratio were found to influence the particles microstructure and morphology. Consequently, changes were obtained in the optical and magnetic properties that were studied through UV-Vis absorption and SQUID, respectively. XRD and Raman spectroscopy studies were carried out to assess the microstructural changes associated with stoichiometry of the particles, and the stability in physiological pH was studied through DLS. The nanoparticles displayed high values of magnetization and heating efficiency for several alternating magnetic field conditions, compatible with biological applications. Hereby, the employed method provides a promising strategy for the development of particles with adequate properties for magnetic hyperthermia applications, such as drug delivery and cancer therapy. [ABSTRACT FROM AUTHOR]

Porous SnO 2 films were successfully prepared using pure tin foils by a convenient electrochemical anodization method in 0.5 M NaOH solutions. Interestingly, the same sample can simultaneously exhibit room temperature ferromagnetism, paramagnetism and diamagnetism. Moreover, the magnetic behavior is related to the direction of the applying magnetic field, showing obvious magnetic anisotropy. A reasonable explanation for this phenomenon was given by analyzing the morphology, magnetic characterization, and spectral analysis of the films, combined with the knowledge of solid physics. This research will be helpful in expanding the application of porous SnO 2 films. [ABSTRACT FROM AUTHOR]

Two‐line ferrihydrite particles are synthesized. Structural characterization of the sample is done with an X‐ray diffractometer, transmission electron microscope, Fourier‐transform infrared spectroscope, and thermogravimetric analyzer. Average particle size is 2 nm. Temperature variation (10–300 K) of zero‐field‐cooled and field‐cooled susceptibility in 500 G applied magnetic field bifurcates at 50 K. The field‐cooled susceptibility below this temperature is almost temperature independent. Magnetization versus applied magnetic field (0–120 kG) data at 300 K are analyzed considering particle size distribution. [ABSTRACT FROM AUTHOR]

In this paper, the magnetic and electrocatalytic properties of hydrothermally grown transition metal doped (10% of Co, Ni, Fe, and Mn) 2H-MoS2 nanocrystals (NCs) with a particle size 25–30 nm are reported. The pristine 2H-MoS2 NCs showed a mixture of canted anti-ferromagnetic and ferromagnetic behavior. While Co, Ni, and Fe doped MoS2 NCs revealed room temperature ferromagnetism, Mn doped MoS2 NCs showed room temperature paramagnetism, predominantly. The ground state of all the materials is found to be canted-antiferromagnetic phase. To study electrocatalytic performance for hydrogen evolution reaction, polarization curves were measured for undoped and the doped MoS2 NCs. At the overpotential of η = −300 mV, the current densities, listed from greatest to least, are FeMoS2, CoMoS2, MoS2, NiMoS2, and MnMoS2, and the order of catalytic activity found from Tafel slopes is CoMoS2 > MoS2 > NiMoS2 > FeMoS2 > MnMoS2. The increasing number of catalytically active sites in Co doped MoS2 NCs might be responsible for their superior electrocatalytic activity. The present results show that the magnetic order-disorder behavior and catalytic activity can be modulated by choosing the suitable dopants in NCs of 2D materials. [ABSTRACT FROM AUTHOR]

The crystal structure, and cryogenic magnetic and magnetocaloric properties in RE2T2Al (RE = Dy, Ho, Er, and Tm; T = Co and Ni) compounds have been investigated. All the compounds belong to an orthorhombic W2B2Co-type structure (Immm space group). A second order paramagnetic to ferromagnetic phase transition exists for RE2Co2Al compounds at TC = 62, 27, 32, and 11.5 K, whereas the compounds of RE2Ni2Al undergo a paramagnetic to antiferromagnetic phase transition with the Néel temperatures (TN) of 19, 12, 12.5, and 6 K for RE = Dy, Ho, Er, and Tm, respectively. Moreover, an additional low temperature magnetic transition occurs for all present RE2T2Al compounds. An obvious hysteresis was observed at a low temperature in the Dy2Co2Al, Ho2Co2Al, and Er2Co2Al compounds. The values of the maximum magnetic entropy change (−ΔSMmax) are 10.4, 11.5, 5.9, 7.7, 6.0, and 16.2 J/kg K for Dy2Co2Al, Ho2Co2Al, Er2Co2Al, Tm2Co2Al, Ho2Ni2Al, and Er2Ni2Al compounds with a field change (ΔH) of 0-5 T, respectively. Moreover, two peaks (or shoulder) in the −ΔSM (T) curves of Ho2Co2Al can be observed, which lead to a wide cooling temperature interval. [ABSTRACT FROM AUTHOR]

Heterostructured magnetic nanoparticles show great potential for numerous applications in biomedicine due to their ability to express multiple functionalities in a single structure. Magnetic properties are generally determined by the morphological characteristics of nanoparticles, such as the size/shape, and composition of the nanocrystals. These in turn are highly dependent on the synthetic conditions applied. Additionally, incorporation of a non-magnetic heterometal influences the final magnetic behavior. Therefore, construction of multifunctional hybrid nanoparticles with preserved magnetic properties represents a certain nanotechnological challenge. Here, we focus on palladium/iron oxide nanoparticles designed for combined brachytherapy, the internal form of radiotherapy, and MRI-guided hyperthermia of tumors. The choice of palladium forming the nanoparticle core is envisioned for the eventual radiolabeling with 103Pd to enable the combination of hyperthermia with brachytherapy, the latter being beyond the scope of the present study. At this stage, we investigated the synthetic mechanisms and their effects on the final magnetic properties of the hybrid nanoparticles. Thermal decomposition was applied for the synthesis of Pd/Fe-oxide nanoparticles via both, one-pot and seed-mediated processes. The latter method was found to provide better control over morphology of the nanoparticles and was therefore examined closely by varying reaction conditions. This resulted in several batches of Pd/Fe-oxide nanoparticles, whose magnetic properties were evaluated, revealing the most relevant synthetic parameters leading to promising performance in hyperthermia and MRI. [ABSTRACT FROM AUTHOR]

In this work, we present eight oxamato complexes of formula (n-Bu4N)[M(HL)4(DMSO)]·nH2O (M = Y3+, La3+, Nd3+, Ho3+) with either _HClppa (= N-(4-chlorophenyl)oxamic acid) or _HFppba (= N-(4-fluorophenyl)oxamic acid) as the HL ligands, n = 2 (_HFppa) or 3 (_HClppa), besides the coordinated dimethylsulfoxide (DMSO) molecule, and tetrabutylammonium (n-Bu4N+) as counterions. All compounds were characterized by elemental analysis, IR spectroscopy, and single-crystal X-ray diffraction. The analysis shows that all mononuclear compounds, with two oxygen atoms from each oxamic acid ligand and a DMSO molecule coordinated to the metal ion, result in a MO9 sphere of coordination. The dc magnetic properties of complexes Nd_HClppa, Nd_HFppa, Ho_HClppa, and Ho_HFppa reveal their paramagnetism. The ac magnetic measurements indicate the existence of slow relaxation of the magnetization for Ho3+ and Nd3+ compounds at low temperatures, suggesting that Ho3+ complexes are single-ion magnets (SIMs) while Nd3+ compounds are field-induced SIMs. Ab initio calculations were performed to determine the crystal-field parameters, which were subsequently used to obtain the best-fit curves of dc magnetic data and simulate susceptibility curves. The latter was consistent with experimental results for each compound, although small differences between compounds with the same lanthanide were not reproduced when all compounds were considered. [ABSTRACT FROM AUTHOR]

We present a theoretical study on the anisotropic magnetocaloric effect and the size-dependent magnetic properties of Fe particles of radii in the range 25–150 Å. An observable increase has been found in the magnetization, of the low radii (25–75 Å) particles, by reducing the temperature to 4 K. The anisotropic isothermal change in entropy ΔSm has been calculated by taking the difference between maximum ΔSm along the easy [100] and hard [111] directions. The maximum anisotropic ΔSm is 0.015 J/kg K for a field change of 500 Oe along the [100] direction. The ΔSm temperature dependence exhibits a table-like plateau for small radii (25–75 Å) and in low fields below 300Oe. This enhances the relative cooling power (RCP) of the Fe element to be 8.11 J/kg for particles of 25 Å radius. Also, the calculation of anisotropic ΔTad was performed along the easy axis and showed an increase in the maximum value around 37% relative to the experimental conventional value. [ABSTRACT FROM AUTHOR]

Tin-doped zinc sulfide was coated onto glass plates and subjected to a post-air annealing treatment at 300 °C for 2 h. The air-annealed thin films were characterized for observing the tailoring in structural, surface, chemical, optical, photoluminescence, and magnetic properties due to annealing. The properties of thin films after air-annealing were compared with as-synthesized Kumar et al. (J. Supercond. Novel Magn. 32(6), 1725-1734, 2019), and vacuum-annealed Kunapalli et al. (Opt. Mater.114, 110961, 2021) thin films. Annealing in presence of air leads to finer crystallite structures of ZnS thin films. The air annealing also enhanced the transmittance property of the thin films. Two prominent peaks at 420 nm and 440 nm were observed in photoluminescence spectra. From magnetic studies, it was found that the films were paramagnetic in nature, and magnetization increased with an increase in the applied field. [ABSTRACT FROM AUTHOR]

(In 1-x Er x) 2 O 3 nanoparticles were synthesized by lyophilization of an aqueous solution of indium and erbium acetates and then applying heat treatments. These nanoparticles were characterized regarding their structural, optical, and magnetic properties over a temperature range of 2–300 K. For x ≤ 0.04, all samples were monophasic, crystallized with cubic structure (Ia-3 space group), and characterized by oxygen vacancies. Er doping reduced the crystallite size and increased the lattice strain. However, no change in energy bandgap was observed after erbium dilution in the oxide matrix. The doped samples were paramagnetic over the entire temperature range, but at low temperatures paramagnetism coexisted with a ferromagnetic phase. The ferromagnetism was attributed to the presence of magnetic polarons acting as mediators of the coupling between the Er3+ ions. The low-temperature segments of the magnetization curves, i.e., M(T< 20 K), were successfully fitted based on the Bound Magnetic Polaron model. [Display omitted] • In2-xErxO3 monophasic NPs were successfully synthesized by lyophilization and heat treatments. • The semiconductor In2O3 was for the first doped with a HRE and the solubility limit for Er was 4%at. • Er doping decreased particle size, increased strain, and did not change the semiconductor bandgap. • In2-xErxO3 is PM at and below RT but a FM phase appears at T < 20 K. • The FM phase is due to bound magnetic polarons formed by Er3+ cations. [ABSTRACT FROM AUTHOR]

Ceria (CeO2) and its solid solutions with Gd2O3 are technologically important and environmentally friendly materials with numerous interesting properties and important applications. Nevertheless, the magnetic properties of ceria are even today not fully understood, and magnetoelastic coupling in pure or doped ceria remains essentially unexplored. This has been so, in part, due to the difficulty of measuring very small magnetostrictive strains in weakly paramagnetic materials. During the last decade, however, technical advances have enabled sensitive and accurate measurements of sample deformation in high magnetic fields. Here, forced magnetostriction (MS) in Gd2O3‐CeO2 solid solution ceramics (Ce1−xGdxO2−x/2, 0 ≤x≤ 1) at room temperature is characterized. In a pulsed magnetic field μ0H≤ 60 Tesla, longitudinal MS strain is observed to depend on the square of the field amplitude and to increase linearly with Gd3+ concentration but is not sensitive to the lattice symmetry of the ceramics. The theory attributes the origin of the observed strain to the single‐ion MS response of Gd3+ to the crystal field via mixing of ground and excited electronic states and covalent hybridization with oxygen ligands. Contributions of charge‐compensating oxygen vacancies and/or Van Vleck paramagnetism to the observed magnetoelastic coupling are determined to be negligible. [ABSTRACT FROM AUTHOR]

A computer modeling (DFT UTPSSh/6-311++G(d,p)) of electronic structures, geometric parameters, energy characteristics, and magnetic properties of the mononuclear cobalt complexes with tetradentate N-donor bases (tris(2-pyridylmethyl)amines and N,N'-dialkyl-2,11-diaza[3.3]-(2,6)pyridinophanes) and o-benzoquinones comprising triangulene organosilicon radicals was performed. Paramagnetism of all states of the studied molecules is predicted. It is ascertained that the electronic configurations and energy characteristics of the isomers of the complexes under study are controlled by alkyl substituents in the ancillary N-donor ligands. The compounds capable of manifesting thermally initiated spin state switching rearrangements via spin-crossover and valence tautomerism mechanisms are revealed. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Molecules with long preserved magnetic moments are perceived as the smallest units for storing bytes, which could bring a new revolution for information technology. However, the rational design of such molecules remains challenging. Here two rigid adamantanol ligand based dysprosium(III) complexes ([Dy(1‐AdO)2(py)5]BPh4 ‐ 1 and [Dy(2‐AdO)2(py)5]BPh4 ‐ 2) with pentagonal‐bipyramidal coordination geometry and local D5h symmetry were successfully prepared, which display excellent single‐molecule magnet (SMM) behavior (Ueff ≈ 1835 K, TBZFC ≈ 24 K, TB100s ≈ 17 K and TBH = 23 K for 1; Ueff ≈ 1756 K, TBZFC ≈ 20 K, TB100s ≈ 16 K and TBH = 23 K for 2) due to the much weakened vibration in low energy regimes. Remarkably, the large energy barriers and high blocking temperatures for these two complexes in solid states are well preserved in solution. This is never observed in previous studies of SMMs, indicating that the adamantanol is rigid and can be introduced to make the composed molecules stable enough to maintain the solid state magnetic property in solution. [ABSTRACT FROM AUTHOR]

The ferrimagnetic mixed-spin ternary nanoisland models with two and three layer structures were set up by the Ising model with spin quantum numbers 1, 3/2 and 1/2. Using the transfer matrix method, we got the magnetization, magnetic susceptibility and ground-state diagram exactly. The results show that the magnetic susceptibility of nanoisland with two-layer structure shows antiferromagnetic behavior, while that of nanoisland with three-layer structure shows antiferromagnetic or ferromagnetic behavior in different parameter areas. The antiferromagnetic behavior shows that the net spin of the ground-state system is zero. The ferromagnetic behavior shows that the magnetic susceptibility diverges at zero temperature, the Curie constant is proportional to the square of the net spin in the ground-state configuration of spins. The magnetization of the three-layer structure in an external magnetic field shows superparamagnetic behavior with many magnetization plateaus. It can be inferred that there should be similar results for finite Ising nanosystems. [ABSTRACT FROM AUTHOR]

This paper reports a potential and easy method to prepare nickel ferrite nanoparticles with improved dielectric and magnetic properties by doping with zinc. The structural studies and Rietveld refinement of the XRD pattern confirm the cubic spinel structure of the ferrite phase belonging to the Fd3m space group. Morphological and elemental composition analyses of the prepared samples are carried out using scanning electron microscopy and energy dispersive spectroscopy (EDAX). The frequency variation of the dielectric constant and ac conductivity have been studied. The dependence of dielectric constant and ac conductivity on the frequency of the alternating applied electric field is explained by the Maxwell–Wagner model. The zinc doping in nickel ferrite nanoparticles is helpful in modifying the dielectric properties and thereby designing materials matching the application requirements. Magnetic measurements were carried out at 300 K and 5 K points toward an enhanced magnetic property in zinc-doped samples. The saturation magnetization value for zinc ferrite nanoparticles is around 23 emu/g at 300 K and 56 emu/g at 5 K which clearly indicates the superparamagnetic behavior of the samples. The maximum value for Ms is obtained for the Ni0.5Zn0.5Fe2O4 sample which is 74 emu/g and 101 emu/g at 300 and 5 K, respectively. The enhanced dielectric and magnetic properties inherited by Zn doping in nickel ferrite (NFO) nanoparticles suggest the improved potential of these superparamagnetic NZFO nanoparticles for various applications. [ABSTRACT FROM AUTHOR]

A medium entropy alloy (Fe63.3Mn14Si9.1Cr9.8C3.8)100-xYx(Y=Ag, Cu) was fabricated via a water cooled copper crucible magnetic levitation melting and copper mold negative pressure suction casting method. The effects of adding Ag and Cu elements micro alloying on the stacking fault energy, microstructure, mechanical properties and magnetic properties of the alloy were studied by XRD, SEM and VSM. The results show that the alloy contains fee phase and low stacking fault energy. The addition of diamagnetic elements Ag and Cu further reduces stacking fault and refines grain size, decreases the yield strength and improves the fracture strength and plasticity. The fracture strength and plasticity of(Fe63.3Mn14Si9.1Cr9.8C3.8)99.6Cu0.4 alloy are up to (2 435 ± 1) MPa and (22.2±0.1)%, respectively, while the relative permeability is just 1.00013, thus indicating excellent mechanical properties and paramagnetism. [ABSTRACT FROM AUTHOR]

Uniform perovskite type SmFeO3 and SmCoO3 nanofibers have been prepared by a simple electrospinning approach and calcination process. The obtained samples had orthorhombic structure and strong absorbance behaviors in UV‐vis regions. The diameters of SmFeO3 and SmCoO3 nanofibers were 220 and 300 nm, respectively. The electrochemical and magnetic properties of SmFeO3 and SmCoO3 were investigated. SmFeO3 and SmCoO3 electrodes exhibited typical pseudocapacitive behaviors owing to the redox reactions of Fe3+/Fe2+ and Co3+/Co2+. At 0.5 A g‐1, the specific capacitances of SmFeO3 and SmCoO3 nanofibers were 90.8 and 126.6 F g‐1, respectively. The high‐performance nanostructured SmFeO3 and SmCoO3 have significantly potential application in supercapacitors. SmFeO3 nanofibers exhibited weak ferromagnetic behavior. SmCoO3 nanofibers presented paramagnetism at high temperature and ferromagnetism at 5 K. [ABSTRACT FROM AUTHOR]

Mn x Zn 1-x Fe 2 O 4 (x = 0–1) solid solution was prepared using the TREG-mediated solvothermal method. 10–12 nm spherical superparamagnetic particles (except for ZnFe 2 O 4) were obtained. At room temperature, the ferrites have lower magnetic saturation (Ms) than magnetite. However, at 10 K, it is precisely the opposite. DRX and EXAFS showed that incorporating Zn2+ ions in tetrahedral A-sites provokes a redistribution of Mn and Fe ions in octahedral B-sites of the mixed spinel structure. For Zn concentrations from x = 0.5 and below, the Mn and Fe ions are almost equally distributed between A and B-sites. Therefore, at low Zn concentrations, the small migration of Fe and Mn ions to B-sites increases the magnetic moment of B sub-lattices and, consequently, the total magnetic saturation. In addition, Mn2+ oxidized to Mn3+ and, simultaneously, Fe3+ reduced to Fe2+, affecting the magnetic properties. The increment of Zn concentration severely reduces the magnetization. [ABSTRACT FROM AUTHOR]

The applicability, peculiarities, and progress of the high resolution 1H, 13C, and 15N NMR spectroscopy for elucidating the spin crossover phenomenon were shown. NMR is quite possible to study such systems, extracting a lot of useful information about the properties of complexes in solution. The use of NMR spectroscopy makes it possible to estimate the structural and dynamic peculiarities of complexes possessing a spin crossover. [Display omitted] The applicability, peculiarities, and progress of the high resolution 1H, 13C, and 15N NMR spectroscopy for elucidating the spin crossover phenomenon were shown. The results obtained by the NMR method are compared with the results found by other physicochemical methods. Though, the coordination environment in a solution can change significantly compared with a solid state. As a result, the magnetic properties of the complex as a whole can also vary significantly. NMR is quite possible to study such systems, extracting a lot of useful information about the properties of complexes in solution. The use of NMR spectroscopy makes it possible to estimate the structural and dynamic peculiarities of complexes possessing a spin crossover. In addition, the presence of a "magnetic response" to changing external conditions provides opportunities for targeted design of NMR sensor systems. [ABSTRACT FROM AUTHOR]

[Display omitted] • Cd x Co 1− x Fe 2 O 4 (0 ≤ x ≤ 07) nanoferrites were synthesized by glycol-thermal process. • XRD and FTIR confirmed single phase spinel structure. • Mossbauer spectroscopy revealed transformation in magnetic phases due to addiction Cd2+ ions. • Improvement in magnetic properties Cd x Co 1- x Fe 2 O 4 oxides. The Cd2+ substituted Co 1- x Fe 2 O 4 with concentrations of (0 ≤ x ≤ 0.7) nano ferrites were synthesized using the glycol-thermal method. X-ray diffraction (XRD) and Fourier-transformed infrared (FT-IR) spectroscopy confirmed the structural formation and nanocrystalline structure of spinel ferrites. Samples possess a cubic spinel lattice structure with crystallite sizes varying between 5.1 nm and 15.5 nm. Transmission electron microscopy (TEM) revealed fine particles which are nearly spherical in shape. The 57Fe Mössbauer spectral studies showed an ordered magnetic spin state for x ≤ 0.5 which transforms to a paramagnetic phase for x ≥ 0.6 due to the weakening of super-exchange interactions. The saturation magnetization (M S) was the highest at x = 0 with a value of 73.3 emu/g and fluctuated between 44.3 emu/g and 19.8 emu/g after the addition of non-magnetic Cd2+ ions. The field dependence of dM / dH curves reveals the finite size effect which leads to the frustration in magnetic moments. [ABSTRACT FROM AUTHOR]

The effect of thermobaric treatment (TBT) at Р = 5.5 GPa T = 1900 °C for 4 h on the concentration of single substitutional atoms (P1 centers) in nitrogen-doped synthetic single crystal Ib type diamonds grown by the temperature gradient high-pressure high-temperature (TG-HPHT) method and on their magnetic properties in the temperature range of 2–300 K was investigated. The initial concentration of P1 centers in 2 crystals was 3.0 × 1019 cm−3 and 5.6 × 1019 cm−3, respectively, which decreased by ~96–98 % after TBT. At T < 10 K, an anomalous hysteresis of the magnetic moment is observed in the range of magnetic fields up to H c = 70 kOe, the amplitude of which is half the value of the paramagnetic saturation moment, corresponding to the number of spins of the P1 centers. The shape of the hysteresis loops after subtracting an intrinsic diamond diamagnetic component and the calculated paramagnetic component indicates a granular (local) superconducting state. The fact that the amplitude of the magnetic moment generated by superconducting currents is equal to half the total number of Bohr magnetons of P1 centers may indicate that elementary currents occur in pairs of adjacent P1 centers. As a result of a decrease in the number of P1 centers in diamonds after TBT, the saturation values of the paramagnetic moment and the amplitude of the diamagnetic moment of the induced superconducting currents decrease proportionally. [Display omitted] • SC component of magnetization at T < 15 K presents in N-doped HPHT diamonds after TBT. • Granular superconductivity magnetization reaches half the paramagnetic component. • Pairs of nitrogen P1 centers create superconducting nanocircuits in diamond. [ABSTRACT FROM AUTHOR]

The magnetic properties of magnetite nanoparticles (Fe3O4 NPs) strongly depend on their chemical and physical parameters, which can be regulated by a controlled synthesis process. To improve the quality of the obtained nanoparticles, their surface is often modified with organic compounds (from the group of surfactants, sugars, proteins, or organic acid). In this study, we synthesized magnetite nanoparticles with a surface modified with the organic compound DMSA. Then, the nanocrystallites were characterized in terms of structure and morphology. To investigate the role of DMSA and to understand the adsorption mechanism, FTIR measurements were carried out. Using Mössbauer spectroscopy, we investigated temperature-induced changes in the magnetic properties of prepared samples. The spectra were recorded in a wide temperature range (from 4 K to 390 K) for two types of samples: powders and ferrofluids with various concentrations. In the case of powder samples, the superparamagnetic doublet appeared at room temperature. For magnetic suspensions, the spectra were more complicated. They consisted of superposition of asymmetrically broadened sextets and doublets, which was caused by the occurrence of long-range dipole-dipole interactions. These interactions affected the magnetic properties of the material and increased the blocking temperature. Additionally, the magnetic hysteresis and zero field cooling-field cooling (ZFC/FC) curves were measured with the use of a vibrating sample magnetometer. [ABSTRACT FROM AUTHOR]

Mössbauer spectra of Feridex, an MRI enhancement agent, show that it contains superparamagnetic γ-Fe2O3 nanoparticles. From spectra in magnetic fields applied at room temperature the magnetic moment of the particles was measured to be 11,250 μB, from which the diameters of the single-domain particles are estimated to be about 8 nm. This is smaller than the hydrodynamic particle size of 30 nm which includes a protective coating of dextran. The particles are monodisperse, as shown by the continuous change from a broad superparamagnetic line to a magnetic 6-line pattern as the temperature is lowered below the blocking temperature TB of about 90 K. The magnetic moments and blocking temperature are consistent with those of γ-Fe2O3 samples of known sizes. [ABSTRACT FROM AUTHOR]

Novel rare-earth-contained W-based in-plane chemically ordered (W 2/3 R 1/3) 2 AlC (R = Gd, Tb, Dy, Ho, Er, Tm and Lu) i -MAX phases have been firstly reported. All are identified to be C 2/ c monoclinic by structural analysis. Magnetic ground state is found to change from linear antiferromagnetism for R = Gd to paramagnetism for R = Lu with gradually decreased ordering temperature with the evolution on magnetic configurations. By exfoliation and delamination, brittle W 1. 33 C MXene fragments have been obtained and demonstrated undesired specific capacitance of 76 F g−1 at 1 A g−1. By making W 1. 33 C/Ti 3 C 2 composite MXene, flexible free-standing paper has been obtained and the specific capacitance is substantially enhanced to 183 F g−1 with good retention, which is the highest performance realized in W 1. 33 C MXene up to now. [Display omitted] [ABSTRACT FROM AUTHOR]

Ternary compounds with the [M6X14]2− (M=Mo, W; X=Cl, Br, I) cluster have been established with several counter cations. Herein, we report examples of the ternary rare‐earth (RE) compounds REW6Cl15 and REW6Cl14. Preparations of the compounds GdW6Cl15, TbW6Cl15 and EuW6Cl14 are accomplished by solid‐state reactions of W6Cl12 and RECl3 (RE=Gd, Tb), or EuCl2 at 575 °C in fused silica tubing. GdW6Cl15 and TbW6Cl15 crystallize in the space group C2/c and EuW6Cl14 in Pn3‾ , isotypic to BiW6Cl15 (REW6Cl15) and PbMo6Cl15 (EuW6Cl14) according to X‐ray powder diffraction. Crystal structures are discussed in the light of related compounds, and properties such as magnetism and photoluminescence are reported. [ABSTRACT FROM AUTHOR]

In this study, a new and systematic approach was taken to study the effect of morphology on the magnetic properties of magnetite nanoparticles. A simple hydrothermal method was used to synthesize spherical, cubic, and rod-shaped nanoparticles. For this purpose, homogeneous solutions of heptahydrate ferro sulfate, deionized water, polyethylene glycol, ammonia, hydrogen peroxide, and alcohol were first made in different proportions. The resulting solutions were heated in an autoclave at 160°C for 5 h to allow the nucleation and growth of the magnetite nanoparticles. The resulting precipitates were then filtered, washed, and dried at 80°C. XRD was utilized to study the phase formation of the synthesized samples and their crystallite size. The morphology of the samples and the particle size were studied using SEM. VSM was used to investigate the magnetic properties. The results showed that spherical, cubic, and rod-shaped magnetite nanoparticles were successfully synthesized without any XRD detectable impurities with the present scan conditions. The crystallite size of the spherical, cubic, and rod-like powders was calculated to be about 17, 22, and 8 nm, respectively, while the average particle size was about 25, 63, and 12 nm, respectively, indicating the polycrystalline nature of the particles, i.e., the particles consisted of many crystallites. All the samples, regardless of the morphology, showed superparmagnetic properties. Magnetite nanoparticles with cubic morphology showed a higher Ms value than the others, while the rod-like nanoparticles exhibited the lowest Ms value. The magnetic saturation values were 60.74, 66.36, and 35.11 emu g−1 for the spherical, cubic, and rod-like particles, respectively. [ABSTRACT FROM AUTHOR]

We report the experimental observation of and theoretical explanation for the reduction of dopant ions and enhancement of magnetic properties in Ce-doped TiO2 diluted magnetic semiconductors from UV-light irradiation. Substantial increase in Ce3+ concentration and creation of oxygen vacancy defects in the sample due to UV-light irradiation was observed by X-ray and optical methods. Magnetic measurements demonstrate a combination of paramagnetism and ferromagnetism up to room temperatures in all samples. The magnetization of both paramagnetic and ferromagnetic components was observed to be dramatically enhanced in the irradiated sample. First-principle theoretical calculations show that valence holes created by UV irradiation can substantially lower the formation energy of oxygen vacancies. While the electron spin densities for defect states near oxygen vacancies in pure TiO2 are in antiferromagnetic orientation, they are in ferromagnetic orientations in Ce-doped TiO2. Therefore, the ferromagnetically-oriented spin densities near oxygen vacancies created by UV irradiation are the most probable cause for the experimentally observed enhancement of magnetism in the irradiated Ce-doped TiO2. [ABSTRACT FROM AUTHOR]

Fe–Ni nanoparticles are attractive candidates for magnetic cores of transformers and inductors that are operated at high frequencies. When applying Fe–Ni nanoparticles in magnetic cores, particle size must be controlled to enhance magnetic properties. A two-step synthetic method can be useful for fabricating size-controlled Fe–Ni nanoparticles. In the first step, Ni nanoparticles are synthesized by reducing Ni (II) acetylacetonate in oleylamine (OA) with trioctylphosphine (TOP). Thereafter, Fe (III) acetylacetonate is reduced and Fe atoms diffuse into the preformed Ni nanoparticles in OA. The size of the Fe–Ni nanoparticles depends on that of the Ni nanoparticles. However, no studies have conducted extensive investigations of their synthesis and magnetic properties with various particle sizes. Here, we attempted particle-size-controlled synthesis of Fe–Ni nanoparticles and investigated their magnetic properties. The particle size of the Fe–Ni nanoparticles was varied between 13.1. and 20.5 nm by varying the size of Ni nanoparticles. The saturation magnetization (Ms) gradually reduced with the decrease in particle size because of the increased amount of oxidized surface atoms and phosphides. Coercive forces (Hc) also decreased as the particle size decreased to 15 nm because of the increased effect of superparamagnetism, while the Hc greatly increased with the particle size reduction below 14 nm because of the ferromagnetism exhibited by the Fe layer owing to undiffused Fe atoms. Thus, using this synthetic method, Fe–Ni nanoparticles with a size of approximately 15 nm can be produced, which have a minimum Hc and are the most appropriate for magnetic cores. [ABSTRACT FROM AUTHOR]

Zinc ferrite (ZnFe2O4) nanoparticles were prepared by chemical co-precipitation method. Structural characterization was performed using X-ray diffraction (XRD) and transmission electron microscopy (TEM). Formation of spinel phase was confirmed from XRD studies. Crystallite size and lattice constant of the prepared sample were calculated. TEM images reveal spherical-shaped particles with nanosized distribution. Room temperature magnetic hysteresis loop was recorded using vibrating sample magnetometer (VSM). The magnetization loops exhibit a very narrow loop and behave like superparamagnetic nature. Using the Langevin function, the magnetic behaviour of the prepared nanoparticles was investigated. From the curve fitting, saturation magnetization and reduced magnetization were determined. As-prepared sample was further annealed at three different temperatures namely 800 °C, 1000 °C, and 1200 °C for 2-h duration. The effects of annealing on the structural and magnetic properties were further investigated using XRD and VSM. The observed results on the magnetic characteristics of ZnFe2O4 and applicability of the Langevin function are being discussed. [ABSTRACT FROM AUTHOR]

Zn1–xCoxO nanoparticles have been prepared by coprecipitation method. X-ray diffraction study confirms the polycrstalline nature with hexagonal wurtzite ZnO structure of the Zn1–xCoxO nanoparticles. The W–H analysis results confirms the mean crystallite size of the Co-doped samples was increased from 62 to 72 nm. All samples have nanocrystalline particles were investigated by field emission scanning electron microscopy. Optical absorption studies showed a red shift absorption spectra due to the incorporation of Co atoms in ZnO lattice. Dielectric constant and dielectric loss were decreasing with increasing Co content. Magnetic hysteresis loops of prepared nanoparticles exhibit paramagnetic behavior at room temperature. [ABSTRACT FROM AUTHOR]

Pure semi-ionic F-doped graphene with the s-F concentration high up to 17.4 at.% (s-FG-17.4) and covalent F-doped graphene with the c-F concentration of 17.8 at.% (c-FG-17.8) were synthesized by fluorination of graphene respectively at the low temperature of 100 °C and the conventional temperature of 200 °C. The electronic and magnetic properties of the two samples were studied. The results show that s-FG-17.4 is metal and exhibits strong ferromagnetism with the Curie temperature of 229 K and high magnetization of 1.1 emu/g; by contrast, c-FG-17.8 is semiconductor and exhibits spin-half paramagnetism with low magnetization of 0.1 emu/g. Thus, this study provided a reliable method to synthesize high-concentration pure s-FG and proposed an effective sp 3 dopants for obtaining metallic and ferromagnetic graphene with high magnetization. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Annealing effect implied oxidation of magnetite and enhanced the crystallinity of mixed nickel-copper and nickel-zinc ferrites; • Morphology observation exhibited agglomerated particles showing irregular shapes, and having homogeneous chemical composition; • 57Fe Mössbauer spectra revealed the superparamgnetic relaxation behaviour for magnetite and nickel-zinc ferrites; • Nickel-copper ferrites Mössbauer spectrum has reflected the ferrimagnetic nature. • Nickel-zinc ferrites show interesting magnetic properties making them a candidate for hyperthermia application. This work aims to investigate the magnetite obtained by coprecipitation, as well as the mixed ferrites of nickel-copper and nickel-zinc. The as-prepared samples were then annealed at a temperature (T an) of 1000 °C. The as-prepared magnetite shows a polycrystalline spinel structure having an average of crystallite size (D XRD) of 8 nm, while other as-prepared mixed ferrites are structurally amorphous. Annealing at T an has resulted in an improvement in the crystallinity of both nickel-copper ferrites (NCF, D XRD = 92 nm) and nickel-zinc ferrites (NZF, D XRD = 83 nm), both of which exhibit a cubic spinel structure. The thermal treatment in air atmosphere has also led to the oxidation of magnetite into hematite. Morphological observations suggest that the magnetite nanoparticles are nearly spherical, whereas the NCF and NZF particles indicate irregular shapes, which tend to aggregate. Magnetic curves reveal that the NCF exhibits a blocking temperature (T B) close to room temperature, while the NZF sample displays the lowest T B at 45 K. Additionally, the NZF exhibits a higher M s value of 80.4 emu/g and displays a narrow hysteresis loop, which makes it suitable for applications in hyperthermia. The 57Fe Mössbauer study on magnetite and NZF indicates broadening spectra, which is due to superparamagnetic relaxation, thus the fit their spectra was established with hyperfine field distribution component. Regarding the NCF Mössbauer spectrum was adjusted by superimposing two sextets reflecting the presence of Fe3+ at the A and B sites of spinel. The hyperfine parameters, including the isomer shift, and hyperfine field, have been systematically reported in the present study. [ABSTRACT FROM AUTHOR]

Multiferroic BiFeO 3 -NiO (BFO-NiO) nanocomposites have been synthesized using sol-gel route and investigated via. the first principle DFT calculations, multiferroic-magnetoelectric response, and extremely low-temperature magnetic analysis. Powder X-ray diffraction (XRD) patterns along with Rietveld refinement data confirmed the phase purity viz. rhombohedral distorted perovskite BiFeO 3 - rock salt type NiO crystal structure and composite formation. Temperature dependent magnetic measurements confirmed the enhancement in the magnetism and the exchange bias effect due to the antiferromagnetic (AFM) and ferromagnetic (FM) exchange coupling interactions. Zero field cooled (ZFC) and field cooled (FC) magnetic results demonstrate the observation of typical superparamagnetic (SP) behavior for all the samples at room temperature whereas at low temperature a transition is reported from SP to quantum superparamagnetic (QSP) state through quantum tunneling of magnetic moment for all samples. Maximum polarization of 5.7μC/cm2 is observed for BFO-20% NiO composition. The noticeable change in the ferroelectric P vs E loops in the presence of external magnetic field confirm the evidence of multiferroic and magnetoelectric coupling behavior in the BFO-NiO nanocomposites. The DFT calculations have been done using WIEN2k software and found in well agreement with the reported experimental results. Further, the suitable temperature dependent magnetic squareness, evidence of considerable magnetoelectric coupling, exchange bias effect and SP nature make the BFO-NiO nanocomposites considerable suitable for various device applications such as information storage, magnetic random access memory, targeted drug delivery, magnetic resonance imaging (MRI), bio-sensing and tailoring other photocatalytic applications. [Display omitted] • Experiment and first principal DFT study of multiferroic-NiO nanocomposites. • Rietveld refinement data confirmed the phase purity. • Confirmation of exchange bias effect, super-paramagnetic behavior. • Ferroelectric and magnetic measurements confirm evidence of multiferroic and magnetoelectric coupling. • Magnetic squareness indicates information storage application. [ABSTRACT FROM AUTHOR]

Effective and targeted delivery of the antitumour drugs towards the specific cancer spot is the major motive of drug delivery. In this direction, suitably functionalised magnetic iron oxide nanoparticles (NPs) have been utilised as a theranostic agent for imaging, hyperthermia and drug delivery applications. Herein, the authors reported the preparation of multifunctional polyethyleneglycol‐diamine functionalised mesoporous superparamagnetic iron oxide NPs (SPION) prepared by a facile solvothermal method for biomedical applications. To endow targeting ability towards tumour site, folic acid (FA) is attached to the amine groups which are present on the NPs surface by 1‐ethyl‐3‐(3‐dimethylaminopropyl) carbodiimide hydrochloride/N‐hydroxysuccinimide chemistry. FA attached SPION shows good colloidal stability and possesses high drug‐loading efficiency of ∼ 96% owing to its mesoporous nature and the electrostatic attachment of daunosamine (NH3+) group of doxorubicin (DOX) towards the negative surface charge of carboxyl and hydroxyl group. The NPs possess superior magnetic properties in result endowed with high hyperthermic ability under alternating magnetic field reaching the hyperthermic temperature of 43°C within 223 s at NP's concentration of 1 mg/ml. The functionalised NPs possess non‐appreciable toxicity in breast cancer cells (MCF‐7) which is triggered under DOX‐loaded SPION. [ABSTRACT FROM AUTHOR]

Computational modeling (DFT UB3LYP/6-311++G(d,p)) of the spatial structure, energy parameters, and magnetic properties of the adducts of fluorinated cobalt(II) bis-diketonates with o‑benzoquinones containing hydrosilicon triangulene moieties has been performed for the first time. Compounds potentially capable of thermally initiated redox-isomeric rearrangements have been revealed. It has been demonstrated that extension of the polycyclic moiety has no effect on the energy differences between the electromers, but leads to an increase in the total spin of the system. The presence of triangulene radical fragments and exchange coupling are responsible for paramagnetism of all the studied molecules. [ABSTRACT FROM AUTHOR]

The aim of this work consists in the use of cashew gum (Anacardium occidentale), a naturally occurring tropical specie from the Brazilian northeastern coast, for the synthesis of CoFe 2 O 4 (CF) and NiFe 2 O 4 (NF) nanoparticles. The structural, morphological and vibrational properties of nanoparticles were characterized by analytical and spectroscopic techniques such as X-ray diffraction (XRD), FTIR, Raman spectroscopy, TEM, SAED and TG. Magnetic properties were investigated through Mössbauer spectroscopy and DC magnetometry. The XRD results showed single phase nanoparticles with space group Fd-3m and crystallite size of 7.4 and 6.0 for CF and NF, respectively. TEM images showed agglomerated particles with mode sizes of 5.0 and 6.5 nm for CF and NF. SAED confirmed the crystalline spinel structure. The TGA and FTIR showed the presence of a carbonaceous material in the samples. FTIR and Raman spectroscopy demonstrated vibrational modes characteristic of metal‑oxygen bonds in the tetrahedral and octahedral sites. Magnetization measurements showed that both samples are superparamagnetic at 300 K. The Mössbauer spectra at 90 K showed the presence of single-phase CF and NF. • Cashew gum (Anacardium occidentale) is used for sol-gel synthesis. • Green synthesis of nanostructured single phases of Ni and Co ferrites • Structural, thermal, magnetic and spectroscopy characterization of ferrites [ABSTRACT FROM AUTHOR]