THE SOL–GEL SYNTHESIS OF RARE-EARTH IONS SUBSTITUTED BARIUM HEXAFERRITES AND MAGNETIC PROPERTIES

2013 ◽  
Vol 27 (26) ◽  
pp. 1350192 ◽  
Author(s):  
S. CAI ◽  
P. H. XIN ◽  
P. F. WANG ◽  
B. B. ZHANG ◽  
Y. B. HAN ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Rare Earth ◽  
Magnetic Moments ◽  
Sol Gel ◽  
Barium Hexaferrite ◽  
Anisotropy Field ◽  
Average Diameter ◽  
Rare Earth Ions ◽  
Barium Hexaferrites ◽  
The Rare Earth

In this paper, a series of rare-earth-doped barium hexaferrite powders ( Ba 0.95 Re 0.05- Fe 12 O 19 and Ba 0.95 Re 0.05 M 0.05 Fe 11.95 O 19: Re = La , Pr , Sm , Nd , Gd , Dy , Yb ; M = Zn 2+, Mn 2+, [Formula: see text]) were synthesized by the sol–gel self-combustion technology. The phase composition and the magnetic properties of the as-prepared barium hexaferrites were characterized and discussed with X-ray diffraction (XRD) and vibrating sample magnetometer (VSM). The results showed that the barium hexaferrites exhibited the magnetoplumbite phase structure with the average diameter of 45 nm. Magnetic properties study revealed that the variation of the saturation magnetization (Ms) was similar with the change of the rare-earth ions radius, but the change of Ms was low. This indicated that the magnetic moments of rare-earth ions could not affect Ms. The magnetocrystalline anisotropy field mainly influenced the anisotropism of hexaferrites, and the coercivity (Hc) of the rare-earth ions doped barium hexaferrites basically decreased with the increasing orbital quantum numbers (except Sm 3+ and Gd 3+). Further study showed the co-addition of Zn 2+ and Mn 2+ did not change the trend of Ms and Hc. Thus, it is concluded that the rare-earth ions played an important role for the anisotropy field of barium hexaferrites.

Structural, Morphological and Magnetic Characterization of Sm-substituted Ni-Zn Ferrite

2020 ◽  
Vol 10 (2) ◽  
pp. 152-156 ◽  
Author(s):  
Muhammad Hanif bin Zahari ◽  
Beh Hoe Guan ◽  
Lee Kean Chuan ◽  
Afiq Azri bin Zainudin
Keyword(s):  
Magnetic Properties ◽  
Rare Earth ◽  
Saturation Magnetization ◽  
Sol Gel ◽  
Magnetic Behavior ◽  
Rare Earth Ions ◽  
Ion Concentration ◽  
Zn Ferrite ◽  
Auto Combustion ◽  
Combustion Technique

Background: Rare earth materials are known for its salient electrical insulation properties with high values of electrical resistivity. It is expected that the substitution of rare earth ions into spinel ferrites could significantly alter its magnetic properties. In this work, the effect of the addition of Samarium ions on the structural, morphological and magnetic properties of Ni0.5Zn0.5SmxFe2-xO4 (x=0.00, 0.02, 0.04, 0.06, 0.08, 0.10) synthesized using sol-gel auto combustion technique was investigated. Methods: A series of Samarium-substituted Ni-Zn ferrite nanoparticles (Ni0.5Zn0.5SmxFe2-xO4 where x=0.00, 0.02, 0.04, 0.06, 0.08, 0.10) were synthesized by sol-gel auto-combustion technique. Structural, morphological and magnetic properties of the samples were examined through X-Ray Diffraction (XRD), Field-Emission Scanning Electron Microscope (FESEM) and Vibrating Sample Magnetometer (VSM) measurements. Results: XRD patterns revealed single-phased samples with spinel cubic structure up to x= 0.04. The average crystallite size of the samples varied in the range of 41.8 – 85.6 nm. The prepared samples exhibited agglomerated particles with larger grain size observed in Sm-substituted Ni-Zn ferrite as compared to the unsubstituted sample. The prepared samples exhibited typical soft magnetic behavior as evidenced by the small coercivity field. The magnetic saturation, Ms values decreased as the Sm3+ concentration increases. Conclusion: The substituted Ni-Zn ferrites form agglomerated particles inching towards more uniform microstructure with each increase in Sm3+ substitution. The saturation magnetization of substituted samples decreases with the increase of samarium ion concentration. The decrease in saturation magnetization can be explained based on weak super exchange interaction between A and B sites. The difference in magnetic properties between the samples despite the slight difference in Sm3+ concentrations suggests that the properties of the NiZnFe2O4 can be ‘tuned’, depending on the present need, through the substitution of Fe3+ with rare earth ions.

Effect of La3+ Substitution on the Structural and Magnetic Properties of Mn-Zn Ferrite Prepared by Sol-Gel Auto-Combustion Method

2018 ◽  
Vol 916 ◽  
pp. 91-95
Author(s):  
Beh Hoe Guan ◽  
Muhammad Hanif bin Zahari ◽  
Kean Chuan Lee
Keyword(s):  
Magnetic Properties ◽  
Rare Earth ◽  
Spinel Ferrite ◽  
Sol Gel ◽  
Combustion Method ◽  
Secondary Phases ◽  
Zn Ferrite ◽  
Auto Combustion ◽  
Structural And Magnetic Properties ◽  
The Rare Earth

Spinel ferrite with the chemical formula of Mn0.5Zn0.5LaxFe2-xO4(x= 0.02, 0.04, 0.06, 0.08, 0.10) were prepared by a sol-gel auto-combustion method. The effect of the rare-earth substitution on the microstructural properties of the synthesized powders were investigated through X-ray diffraction (XRD) and field-emission scanning electron microscopy (FESEM), while for the magnetic properties, vibrating sample magnetometer (VSM) measurements were made. XRD patterns revealed characteristic peaks corresponding to spinel Mn-Zn ferrite structures with accompanying secondary phases, such as Fe2O3and LaFeO3. The initial addition of La3+into the spinel ferrite system resulted in an initial spike of the lattice parameter and crystallite size before proceeding to decrease as the rare-earth content continues to decrease. FESEM micrographs reveals agglomerated particles with considerable grain size distribution. The magnetic properties, especially the saturation magnetization,Ms, was found to decrease with each increase in La3+substitution. The research findings revealed the critical influence of the La3+substitution towards the overall structural and magnetic properties of the Mn-Zn ferrite samples.

Local symmetry and Z-scan analysis of ZnSe/Eu3+ doped sol–gel silica hosts

2010 ◽  
Vol 88 (7) ◽  
pp. 493-500 ◽  
Author(s):  
Siby Mathew ◽  
K. V. Arun Kumar ◽  
C. Sudarsanakumar ◽  
V. P.N. Nampoori ◽  
N. V. Unnikrishnan
Keyword(s):  
Rare Earth ◽  
Sol Gel ◽  
Glass Network ◽  
Local Symmetry ◽  
Wide Distribution ◽  
Rare Earth Ions ◽  
Saturable Absorption ◽  
Rare Earth Ion ◽  
Enhanced Absorption ◽  
The Rare Earth

Vibrational state side-band spectral analysis of silica matrices, doped with ZnSe/Eu3+ ions, associated with the excitation transition 7F0→5D2 is used to analyze the local asymmetry of the rare earth ions in the glass host. The large inhomogeneous linewidth for the ZnSe co-doped samples indicates the wide distribution of the Eu3+ ions in the matrix and is related to the flexibility of the local glass network. The fluorescence spectra reveal that the intensity of the characteristic emission of europium increases considerably in the presence of ZnSe particles. This phenomenon can be explained by the energy transfer resulting from electron–hole recombination in the ZnSe to the rare earth ion. Nonlinear optical absorption of the sample is also investigated at a wavelength of 532 nm, using open aperture Z-scan technique. The sample exhibits reversible saturable absorption (RSA), which is found to depend on excitation fluence. RSA is due to the enhanced absorption resulting from the electron dynamics in nano-crystallites.

Computer Calculations of the Thermally-Induced Magnetic and Electronic Properties of the Rare Earth Compounds RERu2Si2

2005 ◽  
Vol 480-481 ◽  
pp. 617-622
Author(s):  
Rafal Michalski ◽  
Ryszard J. Radwanski
Keyword(s):  
Magnetic Properties ◽  
Rare Earth ◽  
Electronic Properties ◽  
Zeeman Effect ◽  
Magnetic Ordering ◽  
Anisotropy Field ◽  
Magnetic Interactions ◽  
Rare Earth Compounds ◽  
Paramagnetic Region ◽  
The Rare Earth

The aim of this paper is to demonstrate the effectiveness of the calculation method, which takes into consideration the electrostatic ligands field as well as the the magnetic interactions. Our calculations method based on crystal field (CEF) together with the Zeeman effect in one Hamiltonian and allows calculating many of the temperature dependencies of the magnetic and electronic properties of the rare earth compounds. The result of the calculations shows the accuracy of the approach even for the intermetallic compounds. The obtained results for calculations of the compounds of the family in RERu2Si2 (RE – rare-earth element) are fully confirmed the experimental data such as: the easy magnetic direction of all the analyzed compounds, the thermal dependencies of magnetic properties; in particular the giant magnetocrystalline anisotropy of PrRu2S2 with the calculated anisotropy field BA>400T, in-plain anisotropy of ErRu2Si2, the cause of difficulty in magnetic ordering of compounds TmRu2Si2 and YbRu2Si2 as well as effects and dependencies not foreseen before. In this paper we have put together the elementary calculated magnetic properties for the chosen compounds of RERu2Si2 in the paramagnetic region. All Calculations are on the basis of the calculating computer package BIREC 1.51.

MAGNETIC PROPERTIES OF SUPERCONDUCTING nMBa2Cu3Ox:Ag (M = Y, Gd, and Eu) COMPOSITES

1989 ◽  
Vol 03 (16) ◽  
pp. 1251-1265
Author(s):  
C. Y. HUANG ◽  
T. J. LI ◽  
Y. D. YAO ◽  
L. GAO ◽  
Z. J. HUANG ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Rare Earth ◽  
High Temperature ◽  
High Temperature Superconductors ◽  
Hysteresis Loops ◽  
Residual Magnetization ◽  
Rare Earth Ions ◽  
Pinning Force ◽  
Processing Conditions ◽  
The Rare Earth

We measured the M-H hysteresis loops of n YBa 2 Cu 3 O x: Ag (n = 3, 5, and 7) and 3RBa 2 Cu 3 O x: Ag (R = Gd and Eu) as a function of temperature, and found that the residual magnetization and, hence, pinning is independent of n and the rare-earth ions (R and Y), but depends greatly on the processing conditions. These samples exhibit the strongest pinning force for high-temperature superconductors developed to date.

Infrared and Electronic Spectra of Rare Earth Perovskites: Ortho-Chromites, -Manganites and -Ferrites

1970 ◽  
Vol 24 (4) ◽  
pp. 436-445 ◽  
Author(s):  
G. V. Subba Rao ◽  
C. N. R. Rao ◽  
J. R. Ferraro
Keyword(s):  
Magnetic Properties ◽  
Rare Earth ◽  
Transition Metal ◽  
Ir Spectra ◽  
Electronic Spectra ◽  
Transition Metal Ions ◽  
Rare Earth Ions ◽  
Electronic Transitions ◽  
Rare Earth Ion ◽  
The Rare Earth

The electronic and ir spectra of rare earth perovskites of the general formula LnZO3, where Ln is the rare earth ion or yttrium and Z is Cr, Mn, or Fe, have been studied in detail. The results have been discussed in terms of crystallography, magnetic properties, covalency of Ln—O and Z—O bonds, and Goodenough's one electron energy diagrams. In all these compounds the rare earth ions do not markedly affect the electronic transitions of the transition metal ions; the 3 d electrons clearly exhibit localized behavior. Both the electronic and ir spectra of the LnZO3 perovskites are comparable to the spectra of the corresponding transition metal sesquioxides, Z2O3.

scholarly journals Ag-Sensitized Yb3+ Emission in Glass-Ceramics

Micromachines ◽  
2018 ◽  
Vol 9 (8) ◽  
pp. 380 ◽  
Author(s):  
Francesco Enrichi ◽  
Elti Cattaruzza ◽  
Maurizio Ferrari ◽  
Francesco Gonella ◽  
Riccardo Ottini ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Rare Earth ◽  
Near Infrared ◽  
Uv Light ◽  
Sol Gel ◽  
Rare Earth Ions ◽  
Information Storage ◽  
Efficient Energy Transfer ◽  
Doped Materials ◽  
The Rare Earth

Rare earth doped materials play a very important role in the development of many photonic devices, such as optical amplifiers and lasers, frequency converters, solar concentrators, up to quantum information storage devices. Among the rare earth ions, ytterbium is certainly one of the most frequently investigated and employed. The absorption and emission properties of Yb3+ ions are related to transitions between the two energy levels 2F7/2 (ground state) and 2F5/2 (excited state), involving photon energies around 1.26 eV (980 nm). Therefore, Yb3+ cannot directly absorb UV or visible light, and it is often used in combination with other rare earth ions like Pr3+, Tm3+, and Tb3+, which act as energy transfer centres. Nevertheless, even in those co-doped materials, the absorption bandwidth can be limited, and the cross section is small. In this paper, we report a broadband and efficient energy transfer process between Ag dimers/multimers and Yb3+ ions, which results in a strong PL emission around 980 nm under UV light excitation. Silica-zirconia (70% SiO2-30% ZrO2) glass-ceramic films doped by 4 mol.% Yb3+ ions and an additional 5 mol.% of Na2O were prepared by sol-gel synthesis followed by a thermal annealing at 1000 °C. Ag introduction was then obtained by ion-exchange in a molten salt bath and the samples were subsequently annealed in air at 430 °C to induce the migration and aggregation of the metal. The structural, compositional, and optical properties were investigated, providing evidence for efficient broadband sensitization of the rare earth ions by energy transfer from Ag dimers/multimers, which could have important applications in different fields, such as PV solar cells and light-emitting near-infrared (NIR) devices.

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