scholarly journals Structural and Mössbauer Spectral Studies of Nanosized Aluminum Doped Manganese Zinc Ferrites

2008 ◽  
Vol 2008 ◽  
pp. 1-7 ◽  
Author(s):  
R. L. Dhiman ◽  
S. P. Taneja ◽  
V. R. Reddy
Keyword(s):  
Lattice Parameter ◽  
Ion Concentration ◽  
Aluminum Concentration ◽  
Spectral Studies ◽  
Hyperfine Fields ◽  
Ionic Radii ◽  
X Ray ◽  
Manganese Zinc ◽  
Aluminum Ions ◽  
Manganese Zinc Ferrites

Nanoparticles of aluminum-substituted manganese zinc ferrites,Mn1.05Zn0.05AlxFe1.9−xO4with0.4≤x≤1.0were synthesized by solid-state reaction route and characterized by XRD, TEM, and Mössbauer spectroscopy measurements. The particle size is found to very from 46 to 28 nm with increase of aluminum ions concentration. The unit cell parameter “aO” is found to decrease linearly with aluminum ions concentration due to smaller ionic radius of aluminum. The cation distributions were estimated from X-ray diffraction intensities of various planes. The theoretical lattice parameter, bulk density, porosity, X-ray density, oxygen positional parameter, ionic radii, jump length, as well as bonds and edges lengths of the tetrahedral (A-) and octahedral (B-) sites were determined.Fe57Mössbauer spectra recorded at room temperature were fitted with two sextets corresponding toFe3+ions at tetrahedral (A-) and octahedral (B-) sites. The magnetic hyperfine fields at A- and B-sites show a gradual decrease with increase ofAl3+ion concentration, which has been explained on the basis of supertransferred hyperfine field. The cation distribution obtained from X-ray intensities and Mössbauer data indicates a decrease inFe3+(B)/Fe3+(A)ratio with increasing aluminum concentration thereby suggesting a decrease in ferrimagnetic behavior.

scholarly journals Preparation and Characterization of Manganese Ferrite Aluminates

2008 ◽  
Vol 2008 ◽  
pp. 1-7 ◽  
Author(s):  
R. L. Dhiman ◽  
S. P. Taneja ◽  
V. R. Reddy
Keyword(s):  
Mössbauer Spectra ◽  
Spinel Phase ◽  
Lattice Parameter ◽  
Aluminum Concentration ◽  
Site Preference ◽  
X Ray Diffraction ◽  
Hyperfine Fields ◽  
Ionic Radii ◽  
X Ray ◽  
Mossbauer Spectra

Aluminum doped manganese ferritesMnAlxFe2−xO4with0.0≤x≤1.0have been prepared by the double ceramic route. The formation of mixed spinel phase has been confirmed by X-ray diffraction analysis. The unit cell parameter `aO' is found to decrease linearly with aluminum concentration due to smaller ionic radius of aluminum. The cation distributions were estimated from X-ray diffraction intensities of various planes. The theoretical lattice parameter, X-ray density, oxygen positional parameter, ionic radii, jump length, and bonds and edges lengths of the tetrahedral (A) and octahedral (B) sites were determined.57Fe Mössbauer spectra recorded at room temperature were fitted with two sextets corresponding to Fe3+ions at A- and B-sites. In the present ferrite system, the area ratio of Fe3+ions at the A- and B-sites determined from the spectral analysis of Mössbauer spectra gives evidence that Al3+ions replace iron ions at B-sites. This change in the site preference reflects an abrupt change in magnetic hyperfine fields at A- and B-sites as aluminum concentration increases, which has been explained on the basis of supertransferred hyperfine field. On the basis of estimated cation distribution, it is concluded that aluminum doped manganese ferrites exhibit a 55% normal spinel structure.

Structural, Morphological, and Magnetic Properties of Nickel Substituted Cobalt Zinc Nanoferrites at Different Sintering Temperature

2021 ◽  
Vol 7 (2) ◽  
pp. 24-32
Author(s):  
D. Parajuli ◽  
N. Murali ◽  
K. Samatha
Keyword(s):  
Particle Size ◽  
Magnetic Properties ◽  
Sintering Temperature ◽  
Compositional Analysis ◽  
Sintered Sample ◽  
Lattice Parameter ◽  
Nickel Concentration ◽  
Ionic Radii ◽  
X Ray ◽  
Average Lattice

Co-precipitation was used for the preparation of Co0.5-xNixZn0.5Fe2O4 (x = 0 to 0.3) nanoferrites. The inverse spinel structure of the samples was clearly shown by the structural analysis of X-ray Diffractometer (XRD) and Fourier Transform Infrared (FTIR) Spectroscopy. We have studied the effect of sintering temperature (500oC) on the lattice constant and particle size using XRD. The average lattice parameters for the non-sintered and sintered samples were 8.377 Å and 8.354 Å respectively. For the non-sintered sample, the nickel concentration decreases the lattice parameter from 8.354 Å to 8.310 Å due to its smaller ionic radii than that of cobalt. While for a sintered sample at 500oC, the lattice parameter increases for concentration x=0.3 due to the thermal effect. The particle size calculated by Transmission Electron Microscope (TEM) agrees well with that of XRD. The morphological and compositional analysis was done with the help of Scanning Electron Microscopy (SEM) and the attached Energy Dispersive X-ray (EDX) Analyzer. The increasing percentage of nickel with decreasing percentage of cobalt shows that the cobalt is substituted by Nickel. The magnetic properties were studied by Vibrational Spectrometer (VSM). The value of saturation magnetization is higher for x=0.1 but lower for x=0.2 and 0.3 due to their particle size. The hysteresis loop of the samples their superparamagnetic behavior at room temperature.

Analyzing structure factor phases in pure and doped single crystals by synchrotron X-ray Renninger scanning

2013 ◽  
Vol 47 (1) ◽  
pp. 160-165 ◽  
Author(s):  
Zohrab G. Amirkhanyan ◽  
Claúdio M. R. Remédios ◽  
Yvonne P. Mascarenhas ◽  
Sérgio L. Morelhão
Keyword(s):  
Small Difference ◽  
Accurate Determination ◽  
Nickel Sulfate ◽  
Lattice Parameter ◽  
Metallic Ions ◽  
Multiple Diffraction ◽  
Ionic Radii ◽  
X Ray ◽  
Model Structures

X-ray multiple diffraction has been applied to study the substitutional incorporation of Mg2+ions into NSH crystals (nickel sulfate hexahydrate, NiSO4·6H2O). Intensity profiles provide information on invariant phases, while angular positions of the multiple diffractions allow accurate determination of lattice parameters. By increasing the atomic disordering only of O2−sites in model structures of doped NSH, the sense and magnitude of induced phase shifts match those necessary to justify the observed changes in the intensity profiles. Causes of disordering and lattice parameter variation are discussed. Although the amount of extra oxygen disordering is relatively large with respect to the small difference in the ionic radii of the metallic ions, this disordering is beyond the resolution power achievable by analyzing diffracted intensities of isolated reflections, such as in standard crystallographic techniques.

Effect on structural and magnetic properties of aluminum substituted Ni–Zn nanoferrite system prepared via citrate-gel route

2015 ◽  
Vol 29 (06) ◽  
pp. 1550032 ◽  
Author(s):  
B. Rajesh Babu ◽  
M. S. R. Prasad ◽  
K. V. Ramesh
Keyword(s):  
Magnetic Properties ◽  
Spherical Shape ◽  
Xrd Analysis ◽  
Aluminum Concentration ◽  
Secondary Phases ◽  
Ionic Radii ◽  
Gaussian Peak ◽  
X Ray ◽  
Average Grain Size ◽  
Structural And Magnetic Properties

Nickel zinc aluminum nanoferrites with general formula Ni 0.5 Zn 0.5 Fe 2-x Al x O 4(x = 0.0, 0.05, 0.1, 0.15, 0.2 and 0.25) were prepared by citrate-gel autocombustion method and heat treated in air at 1100°C for 4 h. The crystallography, surface morphology and magnetic properties were studied by using X-ray diffraction (XRD), scanning electron microscope (SEM) and vibrating sample magnetometer (VSM), respectively. XRD analysis confirms that the system exhibits polycrystalline single phase cubic spinel structure and absence of any secondary phases. The crystallite size estimated from Scherrer formula for the Gaussian peak (311) has been found to be around 30 nm. The results obtained show that with Al 3+ doping, the lattice parameter decreases due to smaller ionic radii of Al 3+ ions replaces larger Fe 3+ ions. The distribution of Al 3+ ions over tetrahedral (A) and octahedral (B) sites is estimated from X-ray intensity calculations. The arrangement of magnetic ions among the tetrahedral and octahedral sites due to the substitution of Al 3+ ions modifies the saturation magnetization (Ms) and coercivity (Hc). The room temperature magnetization values increases up to x = 0.1 and then decreases for the increase in aluminum concentration above x > 0.1. Surface topography of the powder samples exhibits nearly spherical shape microstructure and the average grain size has been found to be 180 nm (x = 0.05). The observed variations in the structural and magnetic properties are discussed in the light of existing understanding.

Structural, dielectric and impedance spectroscopic studies of Ni0.5Zn0.5−xLixFe2O4 nanocrystalline ferrites

2017 ◽  
Vol 31 (22) ◽  
pp. 1750153 ◽  
Author(s):  
Davuluri Venkatesh ◽  
K. V. Ramesh
Keyword(s):  
Ac Conductivity ◽  
Lithium Concentration ◽  
Combustion Method ◽  
Spectroscopic Studies ◽  
Lattice Parameter ◽  
Ion Concentration ◽  
X Ray Diffraction ◽  
X Ray ◽  
Air Atmosphere ◽  
Auto Combustion

Nanocrystalline lithium substituted Ni–Zn ferrites with composition Ni[Formula: see text]Zn[Formula: see text]Li[Formula: see text]Fe2O4 ([Formula: see text] = 0.00–0.25 in steps of 0.05) were synthesized by the citrate gel auto-combustion method and were sintered at 1000[Formula: see text]C for 4 h in air atmosphere. The structural, dielectric, impedance spectroscopic and magnetic properties were studied by using X-ray diffraction, impedance analyzer and vibrating sample magnetometer respectively. The X-ray diffraction patterns confirm that all samples exhibit a single phase cubic spinel structure. Suitable cation distribution for all compositions has been proposed by using the X-ray diffraction line intensity calculations and the theoretical lattice parameter for each composition was observed in close agreement with the experimental ones and thereby supporting the proposed distribution. An increase in the saturation magnetization was observed up to [Formula: see text] = 0.10 level of Li[Formula: see text] substitution and thereafter magnetization reduced for higher concentrations to the highest level of Li[Formula: see text] substitution. The dielectric constant and the DC resistivity of Ni–Zn–Li ferrites were noticed to decrease with increase in the Li[Formula: see text] ion concentration. The impedance spectroscopic studies by using the Cole–Cole plots were studied in order to obtain the relaxation time, grain resistance and grain capacitance. AC conductivity initially remained almost independent of frequency for lower frequencies and thereafter for higher frequencies the AC conductivity increased with increase of Lithium concentration.

X-ray spectral and Mossbauer investigations of structure defects and the degree of inversion of manganese-zinc ferrites

1982 ◽  
Vol 25 (3) ◽  
pp. 200-203
Author(s):  
P. P. Kirichok ◽  
V. P. Pashchenko ◽  
V. I. Kompaniets ◽  
G. T. Brovkina
Keyword(s):  
Structure Defects ◽  
X Ray ◽  
Manganese Zinc ◽  
Manganese Zinc Ferrites

Synthesis, Characterization and Dielectric Properties of Mn(2-x)ZnxP2O7 Ceramics

2013 ◽  
Vol 802 ◽  
pp. 12-16
Author(s):  
Manoon Sutapun ◽  
Rangson Muanghlua ◽  
Surasak Niemcharoen ◽  
Wanwilai C. Vittayakorn ◽  
Panpailin Seeharaj ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Monoclinic Phase ◽  
Ion Concentration ◽  
X Ray Diffraction ◽  
X Ray ◽  
Manganese Zinc ◽  
Ft Ir ◽  
Ir And Raman ◽  
Sintering Method ◽  
Scanning Electron

Manganese zinc pyrophosphate (Mn(2-x)ZnxP2O7 when x = 0.0, 0.5, 1.0, 1.5 and 2.0) ceramics were fabricated by conventionally mixing oxide using the normal sintering method. The samples were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), Raman spectroscopy and scanning electron microscopy (SEM). The XRD results indicated that synthesized Mn(2-x)ZnxP2O7 systems have a pure monoclinic phase without the presence of phase impurities. The lattice parameters and crystalline sizes analyzed from XRD data were changed depending on the amount of added Zn2+ ion concentration in the Mn2P2O7 structure. The FT-IR and Raman results showed the fundamental vibrations of P2O74-ion and Mn-O or Zn-O, which confirmed the Mn(2-x)ZnxP2O7 formation. In addition, dielectric stability of temperature and frequency was observed in the composition, x = 1.0, with a dielectric constant value of 11.5 at 1 MHz.

Hydrothermal synthesis and sintering of nickel and manganese-zinc ferrites

1997 ◽  
Vol 12 (12) ◽  
pp. 3278-3285 ◽  
Author(s):  
Anderson Dias ◽  
Vicente Tadeu Lopes Buono
Keyword(s):  
Hydrothermal Synthesis ◽  
Processing Time ◽  
Lattice Parameter ◽  
Morphological Parameters ◽  
Sintering Process ◽  
Hydrothermal Conditions ◽  
Manganese Zinc ◽  
Manganese Zinc Ferrites ◽  
Parameter Variations ◽  
Mnzn Ferrites

The influence of the starting materials on the crystalline phases observed after hydrothermal synthesis of nickel and manganese-zinc ferrites was investigated. The combination of sulfates and sodium hydroxide showed the best results for the conditions studied. The morphological parameters of MnZn ferrites produced at different hydrothermal conditions (110–190 °C, 4–30 h) were analyzed. Changes in lattice parameter, particle size, density, size and total volume of pores, and in the surface area of the particles were analyzed as a function of temperature and processing time. The sintering process was employed in order to verify the reactivity of the hydrothermal powders at controlled atmosphere. High density and surface homogeneous ceramic bodies were obtained, without zinc volatilization. Lattice parameter variations were associated with changes in the cations distribution of the spinel during sintering.

scholarly journals Pristine and Magnetic Kenaf Fiber Biochar for Cd2+ Adsorption from Aqueous Solution

2021 ◽  
Vol 18 (15) ◽  
pp. 7949
Author(s):  
Anwar Ameen Hezam Saeed ◽  
Noorfidza Yub Harun ◽  
Suriati Sufian ◽  
Muhammad Roil Bilad ◽  
Zaki Yamani Zakaria ◽  
...  
Keyword(s):  
Adsorption Capacity ◽  
Photoelectron Spectroscopy ◽  
Textural Properties ◽  
Ion Concentration ◽  
Solution Temperature ◽  
Maximum Adsorption Capacity ◽  
Magnetic Biochar ◽  
X Ray ◽  
Study Results ◽  
Capacity Surface

Development of strategies for removing heavy metals from aquatic environments is in high demand. Cadmium is one of the most dangerous metals in the environment, even under extremely low quantities. In this study, kenaf and magnetic biochar composite were prepared for the adsorption of Cd2+. The synthesized biochar was characterized using (a vibrating-sample magnetometer VSM), Scanning electron microscopy (SEM), X-ray powder diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). The adsorption batch study was carried out to investigate the influence of pH, kinetics, isotherm, and thermodynamics on Cd2+ adsorption. The characterization results demonstrated that the biochar contained iron particles that help in improving the textural properties (i.e., surface area and pore volume), increasing the number of oxygen-containing groups, and forming inner-sphere complexes with oxygen-containing groups. The adsorption study results show that optimum adsorption was achieved under pH 5–6. An increase in initial ion concentration and solution temperature resulted in increased adsorption capacity. Surface modification of biochar using iron oxide for imposing magnetic property allowed for easy separation by external magnet and regeneration. The magnetic biochar composite also showed a higher affinity to Cd2+ than the pristine biochar. The adsorption data fit well with the pseudo-second-order and the Langmuir isotherm, with the maximum adsorption capacity of 47.90 mg/g.

scholarly journals Growth of sillenite Bi12FeO20 single crystals: structural, thermal, optical, photocatalytic features and first principle calculations

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Durga Sankar Vavilapalli ◽  
Ambrose A. Melvin ◽  
F. Bellarmine ◽  
Ramanjaneyulu Mannam ◽  
Srihari Velaga ◽  
...  
Keyword(s):  
Single Crystal ◽  
Single Crystals ◽  
Photoelectron Spectroscopy ◽  
Diffraction Method ◽  
Lattice Parameter ◽  
First Principle ◽  
X Ray Diffraction ◽  
X Ray ◽  
First Principle Calculations ◽  
Photodegradation Efficiency

AbstractIdeal sillenite type Bi12FeO20 (BFO) micron sized single crystals have been successfully grown via inexpensive hydrothermal method. The refined single crystal X-ray diffraction data reveals cubic Bi12FeO20 structure with single crystal parameters. Occurrence of rare Fe4+ state is identified via X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS). The lattice parameter (a) and corresponding molar volume (Vm) of Bi12FeO20 have been measured in the temperature range of 30–700 °C by the X-ray diffraction method. The thermal expansion coefficient (α) 3.93 × 10–5 K−1 was calculated from the measured values of the parameters. Electronic structure and density of states are investigated by first principle calculations. Photoelectrochemical measurements on single crystals with bandgap of 2 eV reveal significant photo response. The photoactivity of as grown crystals were further investigated by degrading organic effluents such as Methylene blue (MB) and Congo red (CR) under natural sunlight. BFO showed photodegradation efficiency about 74.23% and 32.10% for degrading MB and CR respectively. Interesting morphology and microstructure of pointed spearhead like BFO crystals provide a new insight in designing and synthesizing multifunctional single crystals.

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