Room Temperature Magnetic Measurements Research Articles

Structural, Magnetic, and Electrical Properties of (1-x) Na0.5Bi0.5TiO3 –(x) NiFe2O4(x = 0.1, 0.3, 0.5, 0.7, and 0.9) Multiferroic Particulate Composite

Multiferroic composites consisting of Na0.5Bi0.5TiO3(NBT) and NiFe2O4(NFO) phases have been synthesized by using sol-gel and metal-organic decomposition (MOD) methods. The X-ray diffraction (XRD) and scanning electron microscopy (SEM) results confirm NBT and NFO phase formation in all composite samples without the presence of any intermediate phases. The phonon vibrational modes of the composite samples are detected by Raman spectroscopy over wavenumber regions from 100 to 1000 cm−1 at room temperature. The dielectric constant and dielectric losses are measured over a wide range of frequencies from 1 kHz to 1 MHz at room temperature. Room temperature magnetization measurements confirm the ferromagnetic behavior of all the composite samples. The observed values of coercivity are significantly lower and lie between 9.5 and 49 Oe only, which signifies the soft magnetic behavior of samples. The highest leakage current density value (3.39 × 10−6) has been observed for 50NBT-50NFO composite in I–V measurements. The present study reveals that NBT-NFO composites could be potential lead-free multiferroic composites and provide an alternative for designing environment-friendly devices.

Dinuclear mixed valence cobalt(II/III) and hetero-tetranuclear cobalt(III)/Na complexes with a compartmental ligand: Synthesis, characterization and use as catalysts for oxidative dimerisation of 2-aminophenol

A N2O4 donor compartmental reduced Schiff base ligand, H2L [(2,2-dimethyl-1,3-propanediyl)bis(iminomethylene)bis(6-methoxyphenol)], obtained on 1:2 condensation of 2,2-dimethyl-1,3-propanediamine with ortho-vanillin followed by reduction with NaBH4 in methanol solution, has been used to prepare two cobalt complexes, [(N3)CoIIIL(µ-OAc)CoII(N3)] (1) and [(μ-N3)2{(AcO)CoIIILNa(CH3OH)}2]·2CH3OH (2). Complex 1 is a dinuclear mixed valence cobalt(III)/cobalt(II) complex with CoIIIO2CoII core. Complex 2, on the other hand, is a tetranuclear cobalt(III)/sodium complex with CoO2Na(N3)2NaO2Co core. Formation of complex 1 or 2 is mainly governed by the amount of cobalt(II) precursors present in the reaction mixture. Each complex has been characterized by elemental and spectral analysis. X-ray diffraction analysis has confirmed their structures. Complex 1 crystallized in a chiral space group Pna21 where both the cobalt(III) and cobalt(II) centers adopt six-coordinate distorted octahedral geometry with cobalt(III) and cobalt(II) centers residing respectivelyat inner N2O2 and outer O4 cavities of the reduced Schiff base. Complex 2 crystallized in triclinic system with P1-space group, where both cobalt(III) and sodium centers adopt distorted octahedral geometry. Oxidation states of cobalt centers have been confirmed by bond length consideration, BVS calculations as well as from room temperature magnetic moment measurement. Both complexes 1 and 2 show phenoxazinone synthase mimicking activity with kcat values 250.21 and 493.73 h−1 respectively.

Analysis of crystal structure and magnetic properties of strontium substituted bismuth ferrite thin films

Thin films of Bi(1−x)Sr x FeO3 (X = 0.00, 0.05, 0.10, 0.20, and 0.30) are synthesized on ultra-cleaned glass substrates by simple spray pyrolysis method at 550 °C. The crystal structures of the thin films are investigated by x-ray diffraction (XRD). The Rietveld refinement data for all the thin films are confirmed a single-phase ABO3 type of rhombohedral structure belonging to the R3c space group. The field emission scanning electron microscopy (FESEM) analysis reveals the size of grains from hexagonal to spherical shape with the addition of Sr doping. The vibrational modes are studied by Raman spectroscopy. The x-ray photoelectron spectroscopy (XPS) analysis unravels the influence of Sr2+ in the creation of Fe2+ defects and oxygen vacancies. The room temperature magnetic measurements of the thin films are carried out within a magnetic field range of ±10 kOe. Magnetic hysteresis loop confirms a significant increase in magnetization in Sr modified bismuth ferrite thin films. The composition i.e. X = 0.20 shows maximum enhancement of magnetic properties with saturation and Remanent magnetization values of 5.99 emu g−1 and 1.77 emu g−1, respectively.

Effect of bismuth (Bi3+) substitution on structural, optical, dielectric and magnetic nature of La2CoMnO6 double perovskite

Double perovskite oxide materials represented as A2BB′O6 have attracted a great attention due to their diverse electrical, magnetic and structural properties. In this report, we discuss synthesis, structural, optical, magnetic and electric nature of the double perovskite manganites of the type La2−xBixCoMnO6 [x = 0.0, 0.1, 0.2]. These solid-state reaction route products with x = 0.0, 0.1 were found monoclinic structured (P 1 21 / n 1) confirmed from the X-ray diffraction data analysis, whereas the sample with x = 0.2 has acquired a new structure confirmed to be cubic (Fm-3 m) with another phase corresponding to Bi2O3 crystallized in monoclinic structure acquiring space groups P 1 21 / c 1. The results of XRD data analysis were re-verified via Rietveld refinement. The phase formation was further verified via Raman and FTIR spectral studies. The samples were investigated for composition and morphology also. The optical bandgap was determined (≈ 1 eV) from the diffuse reflectance UV–Vis spectra. Temperature-dependent dielectric constant and dielectric loss was investigated in the temperature range of 320–90 K at various constant values of applied ac field and the results were exceptionally good. Electrical (dc) resistivity exploiting four-probe technique with and without magnetic field infer the samples are semiconducting in nature. Room temperature magnetic measurement reveals the samples exhibit low magnetic moment which shows linear behaviour in both forward and reverse field values.

Low temperature synthesis of high purity nanoscaled BiFeO3 by a fast polymer solution method and their ferromagnetic behavior

The main obstacle in synthesizing bismuth ferrite is the presence of secondary phases. This paper presents the results of the effect of an unusual chelating agent (polyacrylic acid) on the synthesis of pure and very crystalline BiFeO3 (BFO) nanoparticles. The common chelating system citric acid/ethylene glycol was also evaluated here. The structural (X-ray diffraction and Raman spectroscopy), microstructural and magnetic characteristics were studied. The high resolution XRD confirmed the high purity (>96% in 500 °C) and very crystalline nanoparticulate BFO, without adding any excess of Bi2O3 during the synthesis neither later steps to eliminate secondary phases, i.e., acid leaching or thermal treatment. Thus, the high effectiveness of polyacrylic acid (PAA) as a novel chelating agent in BFO initial crystallization yielded the BFO phase at a temperature lower than that reported in the literature. The nanoparticles (NPs) show a distorted R3c lattice, due to the deformation effect markedly at the lower temperature of synthesis (350 °C), diminishing as the synthesis temperature increases. Raman spectra confirmed the R3c ferroelectric phase of BFO nanoparticles. Room temperature magnetic measurements showed a remarkable ferromagnetic behavior, with a visible saturation magnetization as a result of the small particles.

Remarkable magnetic anisotropy of nickel nanocrystals growth with dominantly exposed {1 1 1} facets in coir fiber pores

The synthesis of nickel nanocrystals in coir fiber pores by a two-step method (co-precipitation and lyophilization) has been demonstrated. XRD analysis proved the face-centered cubic crystal structure of nickel with the space group Fm3¯m. Nickel nanocrystals of 8.5 nm in size with dominantly exposed {111} planes, embedded in a coir fiber matrix, were determined. Scanning electron microscopy clearly showed that the nickel nanocrystals in the coir fiber pores were assembled in large aggregate nanoplates-like structures arrayed along the drawing direction. Room temperature magnetic measurements showed that nickel nanocrystal in the coir fiber exhibit typical ferromagnetic behavior at room temperature. A different response of the magnetization (M⊥ > M||) was also observed when measured with H|| or H⊥ in the drawing direction. This behavior was attributed to a magnetic anisotropy effect due to the preferred orientation of the crystal aggregates.

Crystal structure, microstructure, and broadband electromagnetic response of Al3+-substituted Sr3YCo4O10+δ double perovskites

In this work, we investigate the structural, microstructural, and broadband dielectric and magnetic properties of Sr3YCo4–xAlxO10+δ (x = 0, 0.1, 0.3, 0.5, and 1.0; δ ≤ 1) double perovskite oxides in detail. The compounds were synthesized through solid-state reaction, and characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The broadband dielectric and magnetic properties of the compounds were correlated qualitatively to the multiple valence state of the cobalt ions. The real part of permittivity was found to decrease with increase in Al3+ concentration from 117.3 (x = 0) to 37 (x = 1.0) (at 900 MHz), while the dielectric loss increased from 0.36 to 1.51. The real part of permeability decreased from 1.01 for x = 0 to 0.93 for x = 1.0 (at 900 MHz) accompanied by a decrease in the magnetic loss factor from 0.43 to 0.11. The broadband electromagnetic response was found to be in good agreement with the results obtained from XPS analysis. Impedance analysis revealed that the compounds exhibit a capacitive behavior, which can be attributed to the interfacial polarization due to the pore–grain interfaces. Further, room-temperature magnetic measurements revealed that the ferromagnetic nature of the parent compound diminished with the substitution of aluminum ions as a result of the reduction in oxygen vacancy ordering, which was also evident from FTIR analysis.

A Kinetic study of Tb3+ and Dy3+ co-substituted CoFe2O4 spinel ferrites using temperature dependent XRD, XPS and SQUID measurements

In this research work, we have investigated the structural development of Tb3+ and Dy3+ co-substituted CoFe2O4 ferrites using temperature and time dependent XRD measurements. Sol-gel auto combustion technique was used to synthesized Tb3+ and Dy3+ co-substituted spinel ferrites with composition CoFe2-x-y TbxDyyO4 (x + y = 0.0–0.25). Various characterization techniques such as High temperature XRD, XPS and SQUID were used to observe the Kinetics mechanism as well as the impact of co-substitution on the structural and magnetic properties. Room temperature XRD scans showed that the synthesized materials having single phase and were crystalline in nature. The crystallite size was lied in nano regime ranging from 26.07 to 21.92 nm and lattice parameters were found to be decreased with increasing rare earth metal ions contents. Temperature and time dependent XRD data suggested that structure of investigated samples not degrade even at temperature 900 °C which was maintained for 2 h. The ionic states of Co2+, Tb3+, Dy3+ and Fe3+ were confirmed by X-ray Photoelectron spectrometry measurements along with the binding energies of Co2p, Tb 2p, Dy 2p, Fe 2p which confirmed the tetrahedral and octahedral sites for substituted ions. Room temperature magnetic measurements of annealed nanoferrites were carried out by operating the SQUID magnetometer in VSM mode. The data demonstrated that increasing concentrations of substituent (Tb3+and Dy3+) resulted in the reduction of various magnetic parameters such as remanence, saturation magnetization and Coercivity. The calculated values of saturation magnetization and coercivities were found in the range of 78.1–45.15emu/g and 742–543Oe respectively. This study concluded that cation distribution and crystallite size is effective in controlling the structural, morphological and magnetic properties.

Synthesis, spectral, structure and computational studies of novel transition Metal(II) complexes of (Z)-((dimethylcarbamothioyl)thio) ((1,1,1-trifluoro-4-(naphthalen-2-yl)-4-oxobut-2-en-2-yl)oxy)

Novel transition metal(II) complexes of (Z)-((dimethylcarbamothioyl)thio) ((1,1,1-trifluoro-4-(naphthalen-2-yl)-4-oxobut-2-en-2-yl)oxy) (M = Zn, Cu, Ni, Co, Fe and Mn) obtained from N,N′-dimethyldithiocarbamate (SDTC) and 4,4,4-trifluoro-1-(2-naphthyl)-1,3-butanedione (TFNB) have been synthesized and characterized by diverse analytical and spectroscopic techniques. The bonding nature, stereochemistry and chemical compositions of all the synthesized complexes were inferred from percentage metal, elemental analyses; infrared, electronic, mass spectra, conductivity, melting points, solubility and room temperature magnetic moments measurements. Cu(II) complex assumed a square-planar geometry, Mn(II), Fe(II) and Zn(II) complexes were tetrahedral while Co(II) and Ni(II) complexes are octahedral as deduced from electronic spectra and magnetic moments measurements. The infrared spectra data indicated that coordination with the metal ions in TFNB was via the carbonyl and enol oxygen atoms, while in SDTC the two sulphur atoms are involved. All the synthesized metal(II) complexes were covalent, as revealed by the conductivity measurements in dimethylformamide (DMF). The comparative TGA analysis of the metal complexes exhibit their thermal stability in the order: Zn(II) ˃ Co(II) ˃ Mn(II) ˃ Fe(II) ˃ Cu(II), while the computational studies of the complexes corroborate with the proposed structural geometries. Density functional theory (DFT) calculation showed that the complexes had low energy gap and higher tendency to interact with electron-accepting species.

Facile synthesis of vanadium oxide supported on Fe2O3@SiO2 composite: An effective catalyst for oxidative dehydrogenation reaction of tetrahydrocarbazole

Vanadium oxide (V2O5) was synthesized and deposited over the core-shell Fe2O3@SiO2 nanoparticles by urea-assisted solution combustion method and used in the oxidative dehydrogenation of tetrahydrocarbazole. The resulting composite catalyst “Fe2O3@SiO2@V2O5” was characterized by Fourier transform infrared spectroscopy (FT-IR), powder X-ray diffraction (P-XRD), thermogravimetric analysis/differential thermal analysis (TGA/DTA), scanning electron microscopy (SEM), transmission electron microscopy (TEM), room temperature magnetization measurements and the Branuer-Emmett-Teller (BET) method. TEM results showed the presence of 20-200 nm sized rod-like prismatic V2O5 nanoparticles. The composite catalyst, having a surface area of 18 m2/g and a pore size/pore volume of 6.85 nm/0.03 cm3, displayed ferromagnetic properties conferred by the Fe2O3 core. An increased tetrahydrocarbazole conversion (>99%) and excellent selectivity were obtained with Fe2O3@SiO2@V2O5 compared to pure V2O5 and Fe2O3@SiO2 catalysts. The magnetic composite catalyst exhibited high efficiency and stability as well as reusability.

Exchange bias in Co/CoO thin films deposited onto self-assembled nanosphere arrays

Looking at the importance of exchange bias (EB) studies in novel magnetic systems, magnetic nanocaps consisting of antiferromagnetic (AF)/ferromagnetic (FM) layers were synthesized using nanosphere lithography, followed by ion beam sputtering. For this, CoO/Co/Si and CoO/Co/polystyrene nanosphere (PS) (800 nm diameter) ultra-thin and thick films were prepared by in-situ oxidation. Room temperature magnetization measurements exhibit a clear distinction between the films on PS and those on plane base Si substrate (reference films). Low temperature field cooled measurements on CoO/Co(5 nm)/PS film show a negative EB in both original (−37.4 mT) and trained hysteresis loops (−31.4 mT). However, corresponding reference films show larger EB values in comparison with those of PS substrate counterparts. Due to a higher Co layer thickness, the CoO/Co(100 nm)/PS film shows a lower EB value (−18.2 mT) in comparison with its corresponding CoO/Co(5 nm)/PS ultra-thin film (−37.4 mT). However, for the corresponding reference films, the ultra–thin film shows a higher EB (−68.5 mT) than the thick film (−12.6 mT), which is a generally observed behavior. The overall results are discussed in terms of the curvature induced modifications in the microstructural properties, which cause drastic changes in the magnetic properties of such nanostructures.

Induced ferromagnetism and enhanced optical behaviour in indium-doped barium stannate system

Structural, morphological, optical and magnetic properties of chemically synthesized Indium-doped BaSnO3 (BSO) nanostructures were investigated. XRD results indicated cubic structure from Rietveld refinements and FT-IR studies confirmed the characteristic vibrations for all doped compounds. The presence of oxygen vacancies were derived from the defect-induced Raman modes. Surface morphological studies by HR-SEM showed a significant change from pseudo-cuboids to mixed rods. The presence of oxygen vacancies, oxidation states and elements (Ba, Sn, O and In) were studied by X-ray Photoelectron spectroscopy. UV–Vis and Photoluminescence studies demonstrated a decreasing tendency in bandgap values and the presence of defect states. Interesting defect sites and F-centres were probed by Electron paramagnetic resonance studies. A transition from diamagnetic to ferromagnetic behaviour observed from room temperature magnetic measurements was explained based on F-centre exchange interaction.

Layered double hydroxide–borate composites supported on magnetic nanoparticles: preparation, characterization and molecular dynamics simulations

Magnetic nanocomposites involving tetraborate ion (TB)-intercalated Mg–Al-layered double hydroxide (LDH) shell supported on magnesium ferrite core particles are synthesized, characterized, and compared with their non-magnetic analogues. The compositions of the obtained nanocomposites were determined and structural investigations were made by powder X-ray diffraction and Fourier transform infrared spectroscopy. Particle characteristics were examined by size distribution, specific surface area measurements, scanning electron microscopy and transmission electron microscopy. Room-temperature magnetic measurements were performed with a vibrating sample magnetometer. The dynamics and structure of the interlayer water molecules and borate ions were studied by molecular dynamics simulations. Analytical and modeling studies verified that the TB ions were arranged between the LDH layers in oblique positions. The products were found to carry ca. 6% boron (1017 B atom/μg nanocomposite). The magnetic nanocomposite showed superparamagnetic properties and can potentially find applications in biomedical fields for the site-specific delivery of bio-potent boron agents.

Structural and multiferroic properties of BiFeO3/MgLa0.025Fe1.975O4 nanocomposite synthesized by sol–gel auto combustion route

Nanocomposites of (1−x)BiFeO3(BFO)–xMgLa0.025Fe1.975O4(MLFO) (x = 0.0, 0.1, 0.2, 0.3 and 1.0) for enhanced multiferroic properties have been synthesized via sol–gel auto combustion route. Results of X-ray diffraction pattern, Field emission scanning electron microscopy and energy dispersive spectroscopy revealed the formation of composites and phase analysis for all the samples. Room temperature magnetic measurements (M–H curve) through vibrating sample magnetometer evidenced increasing trend in saturation magnetization (MS) from 0.23 to 5.28 emu/g for x = 0.0 to 0.3 samples, while smaller than MS value (17.06 emu/g) of MLFO nanoparticles. Antiferromagnetic transition or Neel temperature (TN1) for x = 0.0 and x = 0.3 samples were recorded by M–T plot (magnetization vs. temperature curve) and found to be 360 °C and 348 °C, respectively. Room temperature dielectric constant (er) and dielectric loss (tanδ) in the frequency range 100 Hz to 2 MHz were studied for x = 0.0 to 0.3 samples. Temperature-dependent dielectric constant for all the samples exhibited an anomaly near to the antiferromagnetic transition temperature of BFO. Improved ferroelectric property has been observed by virtue of enhancement in the polarization of composite samples. Electric field-guided strain as a function of the applied electric field has shown asymmetric behaviour for pristine BFO and symmetric loop has been observed for all the composite samples with increasing trend in highest peak-to-peak strain value (SP = 0.06 to 0.53% for x = 0.0 to 0.2 and 0.07 for x = 0.3) which makes these materials active for magnetoelectric devices.

Magnetic field dependence of the martensitic transition and magnetocaloric effects in Ni49BiMn35In15

The structural, magnetic, and magnetocaloric properties of the Bi-doped Heusler alloy Ni49BiMn35In15 have been investigated using room temperature X-ray diffraction (XRD) and magnetization measurements in a temperature interval of 5-400 K. The alloy at room temperature was found to be in a mixture of a high temperature austenite phase (AP) and a low temperature martensite phase (MP). A drastic shift in the martensitic transition temperature at the rate of 16 K/T from 197 K to lower temperatures was observed. A kinetic arrest phenomenon of the AP was observed in the magnetization and electrical resistivity measurements during field-cooled (FC) measurements at 5T. A metamagnetic behavior characterized by a jump in magnetization in the isothermal M(H) curves near TM was observed. The maximum value of the magnetic entropy change and refrigerant capacity at Curie temperature were found to be 5.5 Jkg-1K-1 and 312 Jkg-1 for μoΔH = 5T, respectively. A large magnetoresistance value of -56% was found near the martensitic transition.

Structural, morphological and magnetic properties of antiferromagnetic nickel oxide nanoparticles synthesized via sol–gel route

This paper reports the synthesis of pure Nickel Oxide (NiO) nanoparticles, synthesized by Sol-Gel method. The structural, morphological, and magnetic properties of the synthesized NiO nanoparticles were studied using X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Alternating Gradient Magnetometer (AGM). Formation of highly crystalline face centered cubic (FCC) NiO nanoparticles was inferred from XRD analysis. The room temperature magnetization vs magnetic field measurements in the −10 KOe to +10 KOe range confirmed the Antiferromagnetic behavior of the synthesized NiO nanoparticles.

DNA and RNA binding studies on a novel bromo-bridged dimeric copper(II) complex stabilized from a Schiff base ligand

A novel red copper(II) compound, bis(μ-bromo)bis(2-(benzothiazol-2-yl-hydrazono)-1,2-diphenyl-ethanone)-dicopper(II) (1), has been fostered by equimolar reaction of a Schiff-base ligand, 2-(benzothiazol-2-yl-hydrazono)-1,2-diphenyl-ethanone (LH), with copper(II) bromide in satisfactory yield. 1 has thoroughly been characterized by C, H and N elemental analyses, FT-IR and UV-vis (both in solid state and in solution) spectroscopies, and room-temperature magnetic susceptibility and conductivity measurements. Dimeric 1 bears symmetric rare bromo-bridges in its crystal structure. 1 retains its solid-state identity even in a protic solvent like methanol. 1 in methanol displays two-step one-electron redox response. Theoretical calculations based on DFT were executed to probe the electronic structure of 1 and to augment its color. DNA- and RNA-binding aspects of both LH and 1 have been explored. Thermodynamic binding parameters have been determined. LH is a major-groove binder to DNA, while 1 manifests itself as a minor-groove binder. This binding has been corroborated through molecular docking. Nucleic acid binding aspect of such type of rare bromo-bridged red copper(II) dimer is unprecedented.

The effect of Zn2+ substitution on magnetic properties of maghemite nanoparticles, prepared by one-pot coprecipitation method at room temperature

In this work, Zn2+-substituted maghemite (γ-Fe2(1−x/3) ZnxO3, x = 0.0, 0.1, 0.2, 0.3 and 0.4) nanoparticles were synthesized via one-pot coprecipitation method at room temperature. Their structural and magnetic properties were studied by X-ray diffraction (XRD), magnetic thermogravimetry (TG/M/), vibrating sample magnetometry (VSM) and Fourier transform infrared (FTIR) spectroscopy methods. XRD analysis shows that all as-prepared samples have a spinel structure and their lattice constants change from 8.334 to 8.391 A, depending on the Zn2+ content. Mean crystallite sizes of the as-prepared nanoparticles were estimated by Scherrer’s formula, which are between 3.4 and 4.9 nm. FTIR analysis reconfirms maghemite phase formation. Curie temperature of the samples was determined under two different conditions, one in uncapsulated form and another one in vacuumed quartz capsule, using TG/M/ method. The results show that the Curie temperature of the samples, measured in the uncapsulated form, is decreased from 515 to 330 °C as Zn2+ content increases. Also Curie temperature of the capsulated samples exhibits a reduction from 580 to 280 °C. Room-temperature magnetic measurements illustrate that as Zn2+ content increases, saturation magnetization initially increases from 53 emu/g to 54 emu/g for x = 0.1 and then decreases to 42 emu/g. These variations were discussed based on A and B sites occupations by diamagnetic and paramagnetic ions and reduction in A–A, B–B and A–B superexchange interactions, as a result of both increase in lattice constant and presence of more diamagnetic Zn2+ ions in the structure. These nanoparticles are suitable for fabrication of Faraday rotation devices potentially.

Controlled synthesis and self-assembly of ZnFe2O4 nanoparticles into microspheres by solvothermal method

Zinc ferrite (ZnFe2O4) colloidal nanoparticle assemblies (CNAs) were prepared controllably by solvothermal synthesis without the assistance of a template or surfactant. The x-ray diffraction (XRD) results confirm the formation spinel structure of ZnFe2O4 with the grain size around 11 ± 3 nm. Scanning electronic microscope (SEM) images show that the CNAs are sub-microspheres self-assembled by nanoparticles with size about 284–346 nm changed with reaction conditions. The composition of elements Zn, Fe and O in the ZnFe2O4 CNAs is identified by using EDAX analysis. Room-temperature vibration magnetic measurements (VSM) demonstrates the as-obtained ZnFe2O4 CNAs showing superparamagnetic behavior with saturation magnetization values between 58 and 66 emu g−1. The UV–vis diffuse reflectance (UV–vis DRS) analysis revealed that the band gap energy is increased (blue shift) with decrease of particle size. The nitrogen adsorption-desorption analysis shows that CNAs are meso and microporous with a specific surface area from 71.68 to 92.92 m2g−1. The reaction time and different amounts of anhydrous sodium acetate (NaAc) influence the crystallinity, size, magnetic property and surface area of the ZnFe2O4 CNAs.

Influence of transition metals co-doping on CeO2 magnetic and photocatalytic activities

Design and development of novel highly efficient diluted magnetic semiconductors for spintronic devices and photocatalytic application is of great importance. In this regard, we report on the synthesis and analysis of new class of highly efficient pure CeO2, Ce0.42Fe0.04Co0.04O50, Ce0.42Co0.04Ni0.04O50 and Ce0.38Fe0.04Co0.04Ni0.04O50 nanoparticles. The crystal structure, phase, optical characteristics, magnetic properties and photocatalytic characteristics of synthesized nanoparticles were measured using various analytical techniques. The comprehensive structural analyses revealed that incorporation of Fe, Co and Ni ions in host lattice without change their original structure. Presence of defect sites in synthesized nanoparticles was confirmed through photoluminescence studies. Room temperature magnetic measurements revealed that pure CeO2 and Ce0.42Fe0.04Co0.04O50 nanoparticles showed paramagnetic nature as well as Ce0.42Co0.04Ni0.04O50 and Ce0.38Fe0.04Co0.04Ni0.04O50 nanoparticles exhibited mixed behavior of paramagnetic and ferromagnetic characteristics. Further, Ce0.38Fe0.04Co0.04Ni0.04O50 nanoparticles showed better photocatalytic activity with pseudo first order rate constant 0.0157 (min−1) and it is 1.7 times larger than that of pristine CeO2 nanoparticles.