In the present work, Co1-xZnxFe2O4 (x = 0.0, 0.3, 0.5, 0.7 and 1.0) nanoparticles were prepared by chemical co-precipitation method. Prepared Co1-xZnxFe2O4 ferrite powder was sintered at 900 °C for ...4 h after TG-DTA thermal studies. XRD analysis revealed the single-phase cubic structure of Co–Zn ferrite nanoparticles and also studied the variation in structural parameter with increasing Zn concentration. The formation of the ferrite phase was confirmed by studying FTIR spectra. The SEM images shows the agglomeration of spherical grains due to the difference in the magnetic nature of the sample. Peaks of respective elements (Co, Zn, Fe, and O) in EDX spectra show the formation of cobalt zinc ferrite. Variation of energy band gap with increasing zinc concentration in cobalt ferrite studied by UV–Vis. Spectroscopy. The M − H loops revealed that the values of magnetic parameters such as MS, Mr, Hc, nB, and Mr/Ms ratio decrease with increasing Zn2+ content in cobalt ferrite nanoparticles.
•Zn2+ substituted cobalt ferrite nanoparticles have been successfully prepared by wet chemical route.•XRD studies confirmed the formation of cubic spinel structure.•It's infrared, morphological, optical and magnetic properties were investigated.•Magnetic properties were influenced significantly by nonmagnetic Zn2+ ion substitution in cobalt ferrite.•Zn2+ ion substituted cobalt ferrite nanoparticles are desirable in biomedical applications.
This study reports cation distribution, magnetic, and hyperfine interaction studies of Cu
2+
-substituted mixed Ni-Zn nano-spinel ferrites prepared by combustion technique. X-ray diffraction and ...electron microscopy were used to study the structural and morphological aspects of all the samples. Rietveld refined diffraction patterns exhibited a cubic-spinel lattice structure with the
Fd
3
m
space group for all the samples. Morphological investigations revealed the spherical morphology of particles with some agglomeration. The magnetic properties investigated at 300 K and 5 K implied a soft ferromagnetic character of all the samples. The magnetization at 5 K progressively enhanced due to surface effects. Field-cooled and zero-field-cooled measurements indicated net irreversibility for all the samples. Hyperfine interaction studies revealed the ferrimagnetic nature of Cu
2+
-substituted mixed Ni-Zn spinel nano-ferrites. All the obtained results show that the prepared nanoparticles are useful for magnetic fluid hyperthermia and other bio-applications.
Herein, the effect of Cu
2+
substitution on the structural, morphological, cation distribution, magnetic, and Mössbauer properties of mixed Ni-Zn spinel ferrites was studied.
This work focused on the impact of synthesis routes on the structural, microstructural, magnetic, electrical and dielectric characteristics of Mg1−xZnxFe2O4 (x = 0.00, 0.25, 0.50, 0.75, and 1.00) ...nanocrystals manufactured via the ceramic and green approach sol-gel route. The powder X-ray diffraction (XRD) analysis reveals that the entire synthesized ferrite solids crystallize in single phase spinel structure. The XRD outcomes highlight the impact of the synthesis routes and Zn2+ replacement on the morphology, crystallite size and structural parameters of magnesium nano-ferrites. The transmission electron microscopy (TEM) images illustrate that the process of synthesis causes extensive lessening of grain and crystallite sizes. The magnetic study reveals that the magnetic properties of magnesium ferrite can be tuned by zinc substitution. The saturation magnetization (Ms), retentivity (Mr), coercive force (Hc) and magneton number diminutions meaningfully with the replacement of diamagnetic Zn2+ ions in Mg-ferrite for both the synthesized systems. The deterioration of magnetic parameters with Zn2+ substitution can be clarified on the base of the random spin canting model. Likewise, the magnetic parameters, enhanced meaningfully for sol-gel derived samples this can be attributed due to decline of crystallite size effect. The DC electric resistivity displays NTCR behaviour like ideal semiconducting materials for all the produced samples. The DC resistivity values of sol-gel produced samples were found to be little bit higher than that of ceramic derived samples. The experimental dielectric constant as a function of frequency behaviour can be elucidated with the support of the heterogeneous model of the polycrystalline structure of ferrites. The dielectric constant and loss tangent decreases with Zn2+ content for both the systems. The dielectric constant enhances for sol-gel derived samples; however, lower values of loss tangent were found. The obtained outcomes can be suitable for multifunctional applications in electronics devices and biomedical field.
Here, we report the chemical synthesis of Zn
0.7
Mg
0.3
S columnar nanorods onto a commercial glass slide. The synthesized films were used for further studies. Structural, morphological, optical, and ...electrical properties were analyzed via X-ray diffraction, FE-SEM, TEM, UV–Vis spectroscopy, and two-probe I–V characteristics, respectively. A stable hexagonal structure with the nanocrystalline size of the ZnMgS material has been confirmed from X-ray and TEM analysis and also structural parameters were determined. FE-SEM micrographs show the uniformity of the grown nanorods on the surface of the film; combined EDX spectra display the presence of Zn, Mg, and S. UV–Vis absorption spectra show a prominent peak at ~ 310 nm which confirms the blue emission spectra. The semiconducting nature of synthesized ZnMgS films was confirmed by the electrical study and the photosensing ability was examined. Finally, ZnMgS is a direct bandgap semiconductor which is confirmed from first-principle calculations.
Tetravalent titanium (Ti
4+
)-substituted nickel ferrite nanoparticles with varying composition were prepared by standard sol–gel auto-combustion method. The phase identification and nanocrystalline ...nature were studied through X-ray diffraction (XRD) technique. The room temperature X-ray diffraction pattern show only those planes which belong to cubic spinel structure. No extra peak other than cubic spinel structure appeared in the XRD pattern suggesting that the prepared nanoparticles possess single-phase cubic spinel structure except
x
= 0.4, 0.5 and 0.6. The plane (311) observed in the XRD pattern showed maximum intensity and is used to calculate the crystallite size (
t
). The Debye–Scherrer’s formula was used to calculate the crystallite size which was found to vary between 19 and 23 nm for varying Ti composition
x
. The lattice constant (
a
) and other structural parameters were obtained from XRD data. The lattice constant is found to be decreasesing with increase in Ti substitution. The FE-SEM images of typical samples confirmed the spherical shape morphology. The magnetic properties were studied by means of vibrating sample magnetometer and Mossbauer spectroscopy technique. All the samples exhibit a good magnetic property which decreases with Ti substitution. The saturation magnetization goes on decreasing from 43.14 (for
x
= 0.0) to 12.86 (for
x
= 0.5) which may be attributed to the decreasing A–B interaction. The Mossbauer spectrum of typical samples show sextet pattern. The Moosabauer parameters like isomer shift, quadrupole splitting, Line width etc. were obtained. The dielectric parameters such as dielectric constant, dielectric loss and dielectric loss tangent etc. were recorded using vector network analyzer.
Ni
0.65
Zn
0.35
Al
x
Fe
2−x
O
4
that has been synthesized using a solution-gelation method and calcined at 600 °C for 4 h was characterized using X-ray diffraction (XRD), Fourier transform infrared ...(FTIR) spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). A single-phase cubic spinel structure belonging to the Fd-3 m space group was confirmed by Rietveld refinement. The cation distribution that was anticipated using the XRD data deviated from the preferential occupancy, and the results of the magnetization analysis supported this. The two absorption bands in the FTIR spectra corresponding to the tetrahedral and octahedral sites further support the establishment of the ferrite skeleton. Al
3+
doping was found to have a considerable impact on the Debye temperature, bulk modulus, and stiffness modulus measured using FTIR data. Interatomic bonding became stronger, increasing elastic moduli. The morphology was examined using SEM, whose results showed a cluster of grains. Additionally, spherical nanoparticles with an average size of 28 nm were visible in the TEM image, which is in good agreement with the crystallite size given by the Williamson-Hall method. The Mössbauer analysis and M–H data showed a soft magnetic behavior with coercivity fluctuation. According to Arrhenius plots, all samples displayed a semiconducting characteristic. With Al
3+
doping, dielectric studies revealed a declining trend.
Strontium substituted bismuth ferrite (Bi
1−
x
Sr
x
FeO
3
with
x
= 0.05, 0.15 and 0.25) multiferroic nanoparticles were successfully synthesized by a simple sol–gel auto combustion technique to ...study the effect of Sr
2+
varying with a concentration on their structural and multiferroic properties. X-ray diffraction patterns confirmed the phase purity of Bi
1−
x
Sr
x
FeO
3
samples having a hexagonal structure with R3c space group. The lattice parameters ‘
a
’ and ‘
c
’ decrease, whereas the unit cell volume contracts with increasing Sr
2+
concentration in BFO. Fourier transform infrared spectroscopy analysis was employed to study the chemical bonds present. Field-emission scanning electron microscopy images of samples show agglomerated nanoparticles with varying average grain sizes 61 and 32 nm. The elemental composition was confirmed using energy-dispersive spectrum analysis. Vibrating sample magnetometer analysis at room temperature showed a significant change in magnetization on Sr
2+
substituted BFO with increased saturation magnetization value (
M
s
= 5.55 emu/g) at
x
= 0.25 composition.
P
–
E
loop tracer used to study the ferroelectric properties and the observed diverse properties of Sr
2+
substituted BFO show applicability for multifunctional devices like actuators.
In the present work nano-sized zinc and chromium substituted simultaneously in nickel ferrites Ni
1−x
Zn
x
Fe
2−x
Cr
x
O
4,
(Ni–Zn–Cr) nanoparticles with
x
= 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0 were ...successfully synthesized through a sol–gel auto-combustion technique using citric acid as a fuel. All the prepared samples have been irradiated by γ-rays of
60
Co source with 7 Mrad at a dose rate of 0.1 Mrad/h to investigate the irradiation effect on the structural, morphological, magnetic and dielectric properties of all the prepared samples. Ni–Zn–Cr nanoparticles were investigated by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FE-SEM) to study their structural and morphological changes. The magnetic properties were studied by vibrating sample magnetometer (VSM) at room temperature before and after irradiation. XRD patterns confirm the formation of pure mono-phase of a cubic spinel structure for all the prepared samples. The two prominent absorption bands in FT-IR spectra also confirm the formation of the spinel structure. The FE-SEM image of un-irradiated samples show agglomerated and almost spherical shape particles morphology; while γ-irradiated samples show some scratched morphology. Dielectric constant and dielectric loss tangent decreases with an increasing zinc and chromium concentration of the unirradiated and after γ-irradiated. Overall; the structural, morphological, magnetic and dielectric properties of the present samples were significantly altered after γ-irradiation. Therefore, low dielectric constant and dielectric loss tangent is attractive due to its potential in device applications.
In the present study, Li
0.5+0.5x
Ti
x
Fe
2.5−1.5x
O
4
(where, 0.0 ≤ x ≤ 1.0 in step of 0.2) nanoparticles were synthesized via sol–gel auto combustion technique. The nanocrystalline samples exposed ...to
60
Co gamma (γ)-radiation of 5 Mrad dose, to understand its effect on structural, morphological, electrical and dielectric properties. The nanoparticles characterized by X-ray diffraction and field emission scanning electron microscopy (FE-SEM) techniques before and after irradiation. The irradiated samples give good crystallinity, and small crystallite size (~ 25 nm) as compared to pristine samples (~ 45 nm) and the lattice parameter gets decreased up to ~ 0.01 Å. The FE-SEM images of pristine samples show spherical morphology, whereas irradiated samples showed some cracks in it. Temperature-dependent conductivity measured by two probe technique reveals that the conductivity decreases (upto ~ 5 × 10
−5
Ω
−1
) after irradiation by obeying Ohmic nature. The dielectric measurements show the strong influence of irradiation on all the samples.
Investigations on the structural, morphological and magnetic properties of Zn1-xCuxO (x=0.00 and 0.05) nanoparticles synthesized via simple and low cost sol-gel auto combustion technique. The ...synthesized samples were characterized by X-ray diffraction technique (XRD), and vibrating sample magnetometer (VSM). XRD pattern reveals the formation of single phase with hexagonal wurtzite structure of both the synthesized samples. It also confirms the sucssefully incorporation of dopant (Cu2+) into the ZnO lattice. The lattice parameter of Cu2+ doped ZnO is slightly greater than that of pure ZnO nanoparticles. The crystallite size of synthesized samples are as 21 and 19 nm in range. Magnetic study carried out by VSM at room temperature and shows the diamagnetic nature of pure ZnO nanoparticles. After the doping of Cu2+ ions in ZnO changes to ferromagnetic nature. The apperance of ferromagnetism due to the presence of free carriers induced by Cu2+ doped into ZnO nanoparticles.
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