Synthesis of Superparamagnetic Magnesium Ferrite Nanoparticles by Microwave-Hydrothermal Method

2004 ◽  
Vol 818 ◽  
Author(s):  
Seema Verma ◽  
Hari S. Potdar ◽  
Sadgopal K. Date ◽  
Pattayil A. Joy
Keyword(s):  
Size Distribution ◽  
Magnetic Hysteresis ◽  
Ferrite Nanoparticles ◽  
Blocking Temperature ◽  
High Coercivity ◽  
Average Particle ◽  
Zero Field ◽  
Magnesium Ferrite ◽  
Hysteresis Behavior ◽  
Microwave Hydrothermal

AbstractSuperparamagnetic magnesium ferrite, MgFe2O4, nanoparticles were synthesized under mild microwave hydrothermal (MH) conditions. Transmission electron microscopic studies showed that the average particle size of the ferrite obtained is ∼3 nm, with a narrow size distribution. Temperature dependent AC magnetic susceptibility measurements at 2 Oe showed characteristic feature of superparamagnetism with blocking temperature, TB, at 47 K. TB decreases with increasing DC magnetic field as evidenced by zero-field-cooled susceptibility studies at 50 and 500 Oe (TB = 38 and 27 K respectively). As a typical superparamagnetic behavior, the zero-field- cooled and the field-cooled magnetizations diverge below TB. Magnetic hysteresis behavior is observed below TB, with a high coercivity of 185 Oe at 12 K, and magnetic hysteresis behavior disappears when measured above TB. The results indicate that MH method is highly suitable for the synthesis of superparamagnetic ferrite nanoparticles of uniform size distribution.

scholarly journals Iron-Doped Lithium Tantalate Thin Films Deposited by Magnetron Sputtering: A Study of the Iron Role in the Structure and the Derived Magnetic Properties

Crystals ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 50 ◽  
Author(s):  
Sergio David Villalobos Mendoza ◽  
José Trinidad Holguín Momaca ◽  
José Trinidad Elizalde Galindo ◽  
Diana María Carrillo Flores ◽  
Sion Federico Olive Méndez ◽  
...  
Keyword(s):  
Thin Films ◽  
Magnetron Sputtering ◽  
Magnetic Hysteresis ◽  
Hysteresis Loops ◽  
Blocking Temperature ◽  
Ferromagnetic Behavior ◽  
Zero Field ◽  
Cooling Curves ◽  
X Ray Diffraction ◽  
Field Cooling

Fe-doped LiTaO3 thin films with a low and high Fe concentration (labeled as LTO:Fe-LC and LTO:Fe-HC, respectively) were deposited by magnetron sputtering from two home-made targets. The dopant directly influenced the crystalline structure of the LiTaO3 thin films, causing the contraction of the unit cell, which was related to the incorporation of Fe3+ ions into the LiTaO3 structure, which occupied Li positions. This substitution was corroborated by Raman spectroscopy, where the bands associated with Li-O bonds broadened in the spectra of the samples. Magnetic hysteresis loops, zero-field cooling curves, and field cooling curves were obtained in a vibrating sample magnetometer. The LTO:Fe-HC sample demonstrates superparamagnetic behavior with a blocking temperature of 100 K, mainly associated with the appearance of Fe clusters in the thin film. On the other hand, a room temperature ferromagnetic behavior was found in the LTO:Fe-LC layer where saturation magnetization (3.80 kAm−1) and magnetic coercivities were not temperature-dependent. Moreover, the crystallinity and morphology of the samples were evaluated by X-ray diffraction and scanning electron microscopy, respectively.

scholarly journals Magnetic Cobalt and Cobalt Oxide Nanoparticles in Hyperbranched Polyester Polyol Matrix

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
O. I. Medvedeva ◽  
S. S. Kambulova ◽  
O. V. Bondar ◽  
A. R. Gataulina ◽  
N. A. Ulakhovich ◽  
...  
Keyword(s):  
Magnetic Hysteresis ◽  
Average Diameter ◽  
Physicochemical Characteristics ◽  
Blocking Temperature ◽  
Zero Field ◽  
Hyperbranched Polyester ◽  
Polyester Polyol ◽  
Cobalt Oxide Nanoparticles ◽  
Ft Ir ◽  
Co Nanoparticles

A series of cobalt (Co) and its oxides based nanoparticles were synthesized by using hyperbranched polyester polyol Boltorn H20 as a platform and sodium borohydride as a reducing agent. UV, FT-IR, XRD, NTA, and TEM methods were employed to obtain physicochemical characteristics of the products. The average diameter of Co nanoparticles was approximately 8.2±3.4 nm. Their magnetic properties, including hysteresis loop, field-cooled, and zero field-cooled curves were investigated. The nanoparticles exhibit superparamagnetism at room temperature, accompanied by magnetic hysteresis below the blocking temperature.

Superparamagnetic Behavior of Granular Co-C Films Consisting of Nanocrystalline Cobalt Encapsulated in Carbon

2000 ◽  
Vol 614 ◽  
Author(s):  
Hao Wang ◽  
S.P. Wong ◽  
W.Y. Cheung ◽  
N. Ke ◽  
M.F. Chiah ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Rutherford Backscattering Spectrometry ◽  
Magnetic Measurements ◽  
Magnetic Hysteresis ◽  
Blocking Temperature ◽  
Vacuum Arc ◽  
Zero Field ◽  
X Ray Diffraction ◽  
X Ray ◽  
Force Microscopy

ABSTRACTNanocomposite Co-C thin films of about 15 nm thick were prepared by pulsed filtered vacuum arc deposition. The films were characterized by x-ray photoelectron spectroscopy, non-Rutherford backscattering spectrometry, x-ray diffraction, magnetic force microscopy and magnetic measurements. The as-deposited films were amorphous. After annealing at 350°C for one hour in vacuum (< 10−3 Pa), the films were found to consist of nanocrystalline Co grains encapsulated in carbon. The superparamagnetism of the annealed Co36C64 film was demonstrated by the measurement of DC susceptibility and magnetic hysteresis using a SQUID magnetometer. The superparamagnetic relaxation blocking temperature was marked to be about 12K by the peak of the zero-field-cooled magnetization under a field of 100 Oe. The magnetic properties of these annealed granular Co-C films transform from superparamagnetism to ferromagnetism when the Co concentration increases.

Magnetic Properties of Ni Nanoparticles Embedded in Amorphous SiO2

2002 ◽  
Vol 746 ◽  
Author(s):  
Fabio C. Fonseca ◽  
Gerardo F. Goya ◽  
Renato F. Jardim ◽  
Reginaldo Muccillo ◽  
Neftalí L. V. Carreño ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Temperature Dependence ◽  
Excellent Agreement ◽  
Magnetic Moments ◽  
Magnetic Hysteresis ◽  
Blocking Temperature ◽  
Spherical Particles ◽  
Average Particle ◽  
Ni Nanoparticles ◽  
Tem Analysis

ABSTRACTA modified sol-gel technique was used to synthesize nanocomposites of Ni:SiO2 which resulted in Ni nanoparticles embedded in a SiO2 amorphous matrix. Transmission electron microscopy TEM analysis were performed to study the structure and morphology of the magnetic powders. The Ni particles were found to have a good dispersion and a controlled particle size distribution, with average particle radius of ∼ 3 nm. A detailed characterization of the magnetic properties was done through magnetization measurements M(T,H) in applied magnetic fields up to ± 7 T and for temperatures ranging from 2 to 300 K. The superparamagnetic (SPM) behavior of these metallic nanoparticles was inferred from the temperature dependence of the magnetization. The blocking temperature TB, as low as 20 K, was found to be dependent on Ni concentration, increasing with increasing Ni content. The SPM behavior above the blocking temperature TB was confirmed by the collapse of M/MS vs. H/T data in universal curves. These curves were fitted to a log-normal weighted Langevin function allowing us to determine the distribution of magnetic moments. Using the fitted magnetic moments and the Ni saturation magnetization, the radii of spherical particles were determined to be close to ∼ 3 nm, in excellent agreement with TEM analysis. Also, magnetic hysteresis loops were found to be symmetric along the field axis with no shift via exchange bias, suggesting that Ni particles are free from an oxide layer. In addition, for the most diluted samples, the magnetic behavior of these Ni nanoparticles is in excellent agreement with the predictions of randomly oriented and noninteracting magnetic particles. This was confirmed by the temperature dependence of the coercivity field that obeys the relation HC(T) = HC0 [1-(T/TB)1/2] below TB with HC0 ∼ 780 Oe.

scholarly journals Magnetic response of bovine spleen

2019 ◽  
Vol 18 (1) ◽  
pp. 52-58
Author(s):  
Ľubor Dlháň ◽  
Roman Krylov ◽  
Martin Kopáni ◽  
Roman Boča
Keyword(s):  
Magnetic Susceptibility ◽  
Field Dependence ◽  
Bifurcation Point ◽  
Magnetic Hysteresis ◽  
Blocking Temperature ◽  
Magnetic Response ◽  
Zero Field ◽  
Remnant Magnetization ◽  
Paramagnetic Behaviour ◽  
Organic Tissue

Abstract Bovine spleen has been used as a sample for deep magnetochemical investigation. Temperature dependence of the magnetic susceptibility and field dependence of the magnetization reveal a paramagnetic behaviour that violates the Curie law. The zero-field cooled magnetization and field cooled magnetization experiments show the bifurcation point at ca TC = 20 K and the blocking temperature TB = 10 K confirming a dominating portion of ferritin along with the organic tissue. There is a remnant magnetization at temperature below 20 K and the search for the magnetic hysteresis was positive.

scholarly journals Magnetic properties of iron oxide nanoparticles with a DMSA-modified surface

2021 ◽  
Vol 242 (1) ◽  
Author(s):  
K. Winiarczyk ◽  
W. Gac ◽  
M. Góral-Kowalczyk ◽  
Z. Surowiec
Keyword(s):  
Magnetic Properties ◽  
Magnetite Nanoparticles ◽  
Magnetic Hysteresis ◽  
Blocking Temperature ◽  
Synthesis Process ◽  
Physical Parameters ◽  
Zero Field ◽  
Powder Samples ◽  
Surface Modified ◽  
Field Cooling

AbstractThe 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.

scholarly journals Морфологические и структурные особенности формирования наночастиц на основе оксида железа при вакуумно-дуговом распылении

2019 ◽  
Vol 61 (7) ◽  
pp. 1240
Author(s):  
И.В. Карпов ◽  
А.В. Ушаков ◽  
Л.Ю. Фёдоров ◽  
Е.А. Дорожкина ◽  
О.Н. Карпова ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Particle Size ◽  
Crystalline Phase ◽  
Room Temperature ◽  
Discharge Plasma ◽  
Arc Discharge ◽  
Average Particle Size ◽  
Ferrite Nanoparticles ◽  
Blocking Temperature ◽  
Average Particle

Ferrite nanoparticles (Fe3O4) were obtained in low-pressure arc discharge plasma. Studies have shown that the obtained nanoparticles have an average particle size of 9.4 nm, the crystalline phase of magnetite, have superparamegnets at room temperature, and a blocking temperature of 89 K. The behavior of nanoparticles in a magnetic field associated with a large specific surface is discussed.

scholarly journals Magnetic properties of hematite (α − Fe2O3) nanoparticles synthesized by sol-gel synthesis method: The influence of particle size and particle size distribution

2019 ◽  
Vol 70 (7) ◽  
pp. 71-76 ◽  
Author(s):  
Marin Tadic ◽  
Matjaz Panjan ◽  
Biljana Vucetic Tadic ◽  
Jelena Lazovic ◽  
Vesna Damnjanovic ◽  
...  
Keyword(s):  
Particle Size ◽  
Magnetic Properties ◽  
Size Distribution ◽  
Sol Gel ◽  
Blocking Temperature ◽  
Zero Field ◽  
Size Distributions ◽  
Magnetization Curves ◽  
Particle Size Distributions ◽  
Hematite Nanoparticles

Abstract Using the sol-gel method we synthesized hematite (α − Fe2O3) nanoparticles in a silica matrix with 60 wt % of hematite. X-ray diffraction (XRD) patterns and Fourier transform infrared (FTIR) spectra of the sample demonstrate the formation of the α − Fe2O3 phase and amorphous silica. A transmission electron microscopy (TEM) measurements show that the sample consists of two particle size distributions of the hematite nanoparticles with average sizes around 10 nm and 20 nm, respectively. Magnetic properties of hematite nanoparticles were measured using a superconducting quantum interference device (SQUID). Investigation of the magnetic properties of hematite nanoparticles showed a divergence between field-cooled (FC) and zero-field-cooled (ZFC) magnetization curves and two maxima. The ZFC magnetization curves displayed a maximum at around TB = 50 K (blocking temperature) and at TM = 83 K (the Morin transition). The hysteresis loop measured at 5 K was symmetric around the origin, with the values of coercivity, remanent and mass saturation magnetization HC10K ≈ 646 A/cm, (810 Oe), Mr10K = 1.34 emu/g and MS10K = 6.1 emu/g respectively. The absence of both coercivity (HC300K = 0) and remanent magnetization (Mr300K = 0) in M(H) curve at 300 K reveals super-paramagnetic behavior, which is desirable for application in biomedicine. The bimodal particle size distributions were used to describe observed magnetic properties of hematite nanoparticles. The size distribution directly influences the magnetic properties of the sample.

scholarly journals Microstructure and Superparamagnetic Properties of Mg-Ni-Cd Ferrites Nanoparticles

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
M. M. Eltabey ◽  
A. M. Massoud ◽  
Cosmin Radu
Keyword(s):  
Magnetic Hysteresis ◽  
Hysteresis Loops ◽  
Anisotropy Constant ◽  
Blocking Temperature ◽  
Zero Field ◽  
Effective Anisotropy Constant ◽  
Crystallite Sizes ◽  
Coprecipitation Route ◽  
Average Size ◽  
Field Cooling

Magnesium substituted nickel cadmium ferrite nanoparticles MgxNi0.6−xCd0.4Fe2O4(fromx= 0 to 0.6 with step 0.1) have been synthesized by the chemical coprecipitation route. X-ray diffraction (XRD) and infrared spectroscopy (FTIR) revealed that the obtained powders have a single phase of cubic spinel structure. The crystallite sizes calculated from XRD data have been confirmed using transmission electron microscopy (TEM) showing that the powders are consisting of nanosized grains with an average size range 5–1.5 nm. Magnetic hysteresis loops were traced at 6.5 K as well as at room temperature using VSM. It was found that, due to the Mg2+-ions substitution, the values of saturation magnetizationMsfor the investigated samples were decreased, whereas the coercive fieldHcincreased. Both zero field cooling (ZFC) and field cooling (FC) curves are measured in the temperature range (6.5–350 K) and the values of blocking temperatureTBwere determined. No considerable variation in the values ofTBwas observed with increasing Mg-content, whereas the values of the effective anisotropy constantKeffwere increased.

scholarly journals Magnetoliposomes containing magnesium ferrite nanoparticles as nanocarriers for the model drug curcumin

2018 ◽  
Vol 5 (10) ◽  
pp. 181017 ◽  
Author(s):  
Beatriz D. Cardoso ◽  
Irina S. R. Rio ◽  
Ana Rita O. Rodrigues ◽  
Francisca C. T. Fernandes ◽  
B. G. Almeida ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Fluorescence Quenching ◽  
Magnetic Hyperthermia ◽  
Ferrite Nanoparticles ◽  
Blocking Temperature ◽  
Potential Drug ◽  
Magnesium Ferrite ◽  
Superparamagnetic Behaviour ◽  
Maximum Magnetization ◽  
Model Drug

Magnesium ferrite nanoparticles, with diameters around 25 nm, were synthesized by coprecipitation method. The magnetic properties indicate a superparamagnetic behaviour, with a maximum magnetization of 16.2 emu g −1 , a coercive field of 22.1 Oe and a blocking temperature of 183.2 K. These MgFe 2 O 4 nanoparticles were used to produce aqueous and solid magnetoliposomes, with sizes below 130 nm. The potential drug curcumin was successfully incorporated in these nanosystems, with high encapsulation efficiencies (above 89%). Interaction by fusion between both types of drug-loaded magnetoliposomes (with or without PEGylation) and models of biological membranes was demonstrated, using FRET or fluorescence quenching assays. These results point to future applications of magnetoliposomes containing MgFe 2 O 4 nanoparticles in cancer therapy, allowing combined magnetic hyperthermia and chemotherapy.

Sign in / Sign up

Export Citation Format

Share Document