Properties Of Zinc Ferrite Nanoparticles Research Articles

Effect of Mo substitution on structural and magnetic properties of Zinc ferrite nanoparticles

Nano ferrite ZnFe2-xMoxO4 (x = 0.0, 0.1, 0.2, and 0.3) samples were synthesized by using citrate method. The phase purity and the structure parameters were studied using X-ray diffraction, FT-IR spectroscopy, and magnetic measurements. Rietveld analysis of X-ray diffraction data revealed that Mo doping ZnFe2O4 changes the degree of inversion of Zn2+ cations. The oxidation state of Mo was studied by using FTIR analysis. Mo doped ZnFe2O4 has a ferromagnetic properties. The magnetization decreases by the replacement of Fe3+ ions by non-magnetic Mo3+ ions. Mo doped ZnFe2O4 samples have a very small coercive field (Hc), which changes depending on the amount of Mo in the sample and reach its maximum value for ZnFe1.7Mo0.3O4. Cation distribution is proposed in an attempt to explain the experimental results of XRD, IR, and VSM data. The direct proportion between the coercive field and the Fe2+ content in the samples was studied in detailed.

Low temperature processing and magnetic properties of zinc ferrite nanoparticles

Zinc ferrite nanoparticles were successfully synthesized by Pechini process and the effect of the calcination temperature and precursors on microstructure was investigated in detail using XRD, FT-IR, SEM, and TEM techniques. The thermal behavior of polymeric intermediates was studied by STA (TG–DTG–DTA) thermograms. Magnetic properties were studied by VSM technique. Results indicated that nanocrystalline zinc ferrite particles with a single-phase spinel structure were obtained. The nanoparticles possessed a spherical morphology with a particle size of 18–62nm depending on the calcination temperature and precursor where higher calcination temperatures resulted in larger particles. It was also found that larger particles formed when polyethylene glycol-1000 (PEG) is used as precursor, while using ethylene glycol (EG) leaded to a smaller particle size. Magnetic properties of the samples were found to be greatly affected by the average crystallite size. The saturation magnetization values increased from 0.72 to 7.21emu/g when the calcination temperature was raised from 400 to 900°C. At a constant calcination temperature, the samples prepared with EG showed lower magnetization than those prepared with PEG. Results also showed that the utilization of PEG precursor decreased the porosity content of polymeric intermediates, which caused a poor combustion with long duration resulting in residual organic impurities in the samples. We show that magnetic characteristics of zinc ferrite nanoparticles can be precisely tuned by changing the calcination temperature and the precursors, expanding the range of practical applications of this material.

Effect of Particle Size on the Structural and Magnetic Properties of Nanocrystalline Zinc Ferrite

ZnFe 2 O 4 is one of the most important technological material having applications in radio engineering, radio technology, semiconductors, bio-medical applications etc. ZnFe 2 O 4 when in bulk form shows paramagnetic behavior at room temperature. When ZnFe 2 O 4 is synthesized by some techniques it was possible to see the ferromagnetic behavior. Also, ZnFe 2 O 4 in nanocrystalline form exhibit different magnetic properties. Therefore in the present work we intend to present the properties of particle size behavior of ZnFe2O4 nanoparticles. ZnFe 2 O 4 nanoparticles were synthesized by oxalic acid based precursor method. The obtained ZnFe 2 O 4 nano powders were thermally annealed from 300 to 600 °C. The structural and magnetic characterization were measured using X-ray diffraction (XRD), scanning electron microscope (SEM), IR measurements and vibrating sample magnetometer (VSM). XRD patterns clearly showed the formation of zinc ferrite. The particle size was observed to increase from 19 to 35 nm with increasing annealing temperature. The lattice constants were observed to decrease with increasing particle size. The nanoparticles size were confirmed using SEM measurements. IR measurements were carried to confirm the phase formation of ZnFe 2 O 4 nanoparticles. The Infrared spectra showed the characteristic features of vibrational bands corresponding to spinel ferrite. Room temperature ferromagnetic properties were observed for zinc ferrite having particle sizes 19 and 21 nm. For the particle size 29 and 35 nm it showed paramagnetic nature. The magnetic properties of zinc ferrite nanoparticles were observed to be dependent on the particle size. Keywords: Nanoferrites Zn ferrite Structural properties Magnetic properties

Magnetic Properties of Zinc Ferrite Nanoparticles Synthesized by Coprecipitation Method

The influence of the precipitant and ferric concentration on the magnetic properties of coprecipitated zinc ferrite nanoparticles has been investigated. The nanoparticles were characterized using X-ray diffraction, scanning and transmission electron microscope, and vibrating sample magnetometer techniques. The results showed that the single-phase zinc ferrite with partially inverse spinel structures can be formed at high concentrations. The inversion coefficient calculated by the Rietveld method decreases with increasing of the concentrations, may be due to the crystal growth. The magnetic measurements exhibited that the coprecipitated zinc ferrite nanoparticles were superparamagnet and magnetization decreases with increasing of the concentrations through decreasing of inversion coefficient.

An X-ray absorption spectroscopy study of the inversion degree in zinc ferrite nanocrystals dispersed on a highly porous silica aerogel matrix

The structural properties of zinc ferrite nanoparticles with spinel structure dispersed in a highly porous SiO(2) aerogel matrix were compared with a bulk zinc ferrite sample. In particular, the details of the cation distribution between the octahedral (B) and tetrahedral (A) sites of the spinel structure were determined using X-ray absorption spectroscopy. The analysis of both the X-ray absorption near edge structure and the extended X-ray absorption fine structure indicates that the degree of inversion of the zinc ferrite spinel structures varies with particle size. In particular, in the bulk microcrystalline sample, Zn(2+) ions are at the tetrahedral sites and trivalent Fe(3+) ions occupy octahedral sites (normal spinel). When particle size decreases, Zn(2+) ions are transferred to octahedral sites and the degree of inversion is found to increase as the nanoparticle size decreases. This is the first time that a variation of the degree of inversion with particle size is observed in ferrite nanoparticles grown within an aerogel matrix.

Structural characterization and magnetic properties of superparamagnetic zinc ferrite nanoparticles synthesized by the coprecipitation method

Single phase zinc ferrite (ZnFe2O4) nanoparticles have been prepared by the coprecipitation method without any subsequent calcination. The effects of precipitation temperature in the range 20–80°C on the structural and the magnetic properties of zinc ferrite nanoparticles were investigated. The crystallite size, microstructure and magnetic properties of the prepared nanoparticles were studied using X-ray diffraction (XRD), Fourier transmission infrared spectrum, transmission electron microscope (TEM), energy dispersive X-ray spectrometer and vibrating sample magnetometer. The XRD results showed that the coprecipitated nanoparticles were single phase zinc ferrite with mixture of normal and inverse spinel structures. Furthermore, ZnFe2O4 nanoparticles have the crystallite size in the range 5–10nm, as confirmed by TEM. The magnetic measurements exhibited that the zinc ferrite nanoparticles synthesized at 40°C were superparamagnetic with the maximum magnetization of 7.3emu/g at 10kOe.

Magnetic behaviour of nanosized zinc ferrite under heavy ion irradiation

Present investigation reports the effect of 100 MeV oxygen beam on the magnetic properties of zinc ferrite nanoparticles. The nanoparticles for this study were synthesized by using the nitrates of zinc and iron in the matrix of citric acid and by sintering the precursor at 500 and 1000 C. Both these samples were irradiated by 100 MeV oxygen beam with two different fluence 1 � 10 13 and 5 � 10 13 ions/cm 2 . Besides the presence of cubic spinel phase, ZnO phase appears after the irradiation in both the samples. A decrease in average particle size was observed in the irradiated samples as estimated by X-ray diffraction pattern. The magnetization versus applied field curves show the decrease in magnetization with the fluence of the beam, which is attributed to the ZnO phase. The thermal magnetization curve for the sample ZF500 shows almost constant value of blocking temperature after irradiation whereas for ZF1000 it increases from 18 K to 32 K at a fluence of 5 � 10 13 ions/cm 2

Gas‐Sensing Properties of Zinc Ferrite Nanoparticles Synthesized by the Molten‐Salt Route

Zinc ferrite (ZnFe2O4) nanoparticles have been synthesized at 700°C using sodium chloride as a growth inhibitor. Single‐phase formation of spinel zinc ferrite having crystallite size in the range of 15–20 nm was observed by XRD and confirmed by TEM. In the present work, the gas‐sensing properties of these zinc ferrite nanoparticles toward ethanol, LPG, H2, NOx. SOx, and H2S have been studied. It was found that they exhibit excellent selective sensitivity toward 200 ppm of H2S at the operating temperature of 250°C, and thus this nanosized ferrite is expected to be useful in an industrial application as a potential H2S gas sensor.

Magnetic properties of zinc ferrite nanoparticles synthesized by hydrolysis in a polyolmedium

Highly crystalline, nanometre sizedZnFe2O4 particles with different diameters, 6.6 and 14.8 nm, were prepared by forced hydrolysis in apolyol medium. The DC magnetic properties exhibit a strong dependence on the particle sizeas a result of the unusual cation distribution. They clearly establish their superparamagneticcharacter at room temperature and the occurrence of ferrimagnetic or ferromagnetic ordering atlow temperature. The magnetization is found to increase with grain size reduction. The57Fe Mössbauer spectra were recorded at 300 and 4.5 K. There is no evidence for the presence of theFe2+ charge state, confirming the perfect stoichiometry of the two samples. At 300 K, theMössbauer spectra consist of doublets due to the superparamagnetic behaviour whereas at4.5 K they reveal a magnetically blocked state. Mössbauer spectra at 10 K in anexternal 6 T magnetic field applied parallel to the direction of the gamma raysclearly show a close to collinear Néel-like ferrimagnetic ordering for the 6.6 nmparticles and a canted Yafet–Kittel-like ferrimagnetic ordering for the 14.8 nm ones.