Influence of La, Mn and Zn Substitution on the Structure, Magnetic and Absorption Properties of M-Type Barium Ferrites

2020 ◽  
Vol 855 ◽  
pp. 145-153
Author(s):  
Didin Sahidin Winatapura ◽  
Deswita ◽  
Ari Adi Wisnu ◽  
Setyo Purwanto ◽  
Y.F. Buys
Keyword(s):  
Electron Microscope ◽  
Rietveld Method ◽  
Structural Parameters ◽  
Lattice Parameter ◽  
Absorption Properties ◽  
Fine Grained ◽  
Zn Substitution ◽  
Transmission Electron ◽  
Barium Ferrites ◽  
Scherrer Formula

A series of M-type barium ferrites with chemicals composition BaFe12O19 and Ba0.7La0.3Fe(12-2x)(MnZn)xO19 (with x = 0.0, 0.2, 0.5) were synthesized using a chemical coprecipitation based technique. The sample was then called as BFO and BLF, BLFMZ-02 and BLFMZ-05, respectively. The structural parameters were measured by applying the full pattern fitting of Rietveld method using Fullprof program. The crystallite size was calculated using Scherrer formula and Williamson-Hall analysis method, and also confirmed by scanning electron microscope (SEM) and transmission electron microscope (TEM). The morphology of particle is composed of fine-grained aggregates with particle size distributions in the range of 70nm - 160nm. The lattice parameter (a = b and c), cell volume (Vcell) and density (ρ) of the samples were found to be changed with La, Mn and Zn substitution due to the dissimilar cationic radii of Ba2+ (1.49Å), La3+ (1.22Å), Fe3+ (0.64Å), Mn3+ (0.89Å) and Zn2+ (0.76Å) ions. The results of sample measurements with Vibrating Sample Magetometer (VSM) indicate that the magnetic behaviours showed that the saturation magnetization (Ms) increased gradually with the substitution of La3+, Mn3+ and Zn3+ ions, whereas the coercivity (Hc) was increase with addition of La3+ ions and then decrease significantly with the addition of Mn3+ and Zn2+ ions. The vector network analyzer (VNA) revealed that microwave absorption measured within 7 – 15 GHz frequency range indicated optimum reflection loss (RL) of-21.50dB at 10.5GHz for BLMZ-02 sample.

Measurement of lattice parameter at the nanometer scale using convergent-beam microdiffraction from a thermal emission source

1993 ◽  
Vol 51 ◽  
pp. 690-691
Author(s):  
W. T. Pike
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Thermal Emission ◽  
Lattice Parameter ◽  
Scanning Transmission Electron Microscope ◽  
Emission Source ◽  
Device Structure ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Convergent Beam

With the advent of crystal growth techniques which enable device structure control at the atomic level has arrived a need to determine the crystal structure at a commensurate scale. In particular, in epitaxial lattice mismatched multilayers, it is of prime importance to know the lattice parameter, and hence strain, in individual layers in order to explain the novel electronic behavior of such structures. In this work higher order Laue zone (holz) lines in the convergent beam microdiffraction patterns from a thermal emission transmission electron microscope (TEM) have been used to measure lattice parameters to an accuracy of a few parts in a thousand from nanometer areas of material.Although the use of CBM to measure strain using a dedicated field emission scanning transmission electron microscope has already been demonstrated, the recording of the diffraction pattern at the required resolution involves specialized instrumentation. In this work, a Topcon 002B TEM with a thermal emission source with condenser-objective (CO) electron optics is used.

Development of Electroless Ni-P/NRAM Nanocomposite Powder with Enhanced Microwave Absorption Properties

2009 ◽  
Vol 67 ◽  
pp. 59-64 ◽  
Author(s):  
Rahul Sharma ◽  
Ramesh Chandra Agarwala ◽  
Vijaya Agarwala
Keyword(s):  
Electron Microscope ◽  
Microwave Absorption ◽  
Radiation Power ◽  
Nanocomposite Powder ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Radar Absorbing Material ◽  
Transmission Electron ◽  
Absorbing Material ◽  
Nanocomposite Powders

Nano radar absorbing material (NRAM) i.e. BaMe2Fe16O27 (Me2+=Fe2+) powder (10 nm) is coated with amorphous Ni-P nano layer (5-10 nm) by using electroless (EL) technology to develop EL Ni-P/NRAM nanocomposite powder. The experimental processes parameters and EL Ni-P bath composition were optimized to obtain the deposition. As-deposited nanocomposite powder was microwave annealed (MWA) with increasing radiation power from 160 to 760 watts for 5 minutes. The surface morphology, elemental contents, phase transformation and magnetic properties of NRAM powders were examined under field emission scanning electron microscope (FESEM), transmission electron microscope (TEM), X-ray diffraction (XRD) and vibrating sample magnetometer (VSM) respectively. Maximum reflection loss (RL) 33.75 dB at 15.80 GHz for nanocomposite powder MWA at 760 watt was obtained the absorption range under −15 dB is from 13.76 to 16.77 GHz with 2 mm thickness layer in Ku Band. Excellent microwave absorption properties due to accurate electromagnetic (EM) match in the nanocomposite microstructure, a strong natural resonance and multipolarization. Such (Ni+ Ni3P)/NRAM nanocomposite powders may be attractive candidates for EM absorption.

XRD characterization of highly dispersed metal catalysts on carbon support

1993 ◽  
Vol 8 (8) ◽  
pp. 1829-1835 ◽  
Author(s):  
Paolo Scardi ◽  
Pier Luigi Antonucci
Keyword(s):  
Particle Size ◽  
Supported Catalysts ◽  
Profile Analysis ◽  
Rietveld Method ◽  
Carbon Support ◽  
Lattice Parameter ◽  
Microstructural Parameters ◽  
Transmission Electron ◽  
Supported Pt Catalysts ◽  
Highly Dispersed

Carbon-supported Pt catalysts were prepared from H2PtCl6 or K2PtCl6 aqueous solutions. Particle size and structure after several thermal activation treatments were studied by X-Ray Diffraction (XRD), Transmission Electron Microscopy (TEM), and Cyclic Voltammetry (CV), and the results of the three techniques were compared. As the catalysts were highly dispersed on an amorphous support, a conventional XRD profile analysis for crystallite size determination could not be performed properly, because of the strong overlapping between the broad Pt peaks superposed to the halos of the amorphous phase. Thus, a new procedure of whole XRD pattern fitting, based on the Rietveld method, was used to have reliable data of Pt particle size (surface area) and lattice parameter. All structural and microstructural parameters were refined within the same procedure, also considering the transparency of the carbon supported catalysts and minimizing the effect of the amorphous background. The method can also take into account the presence of bimodal particle size distributions, which is difficult to study by CV or TEM.

MICROWAVE ABSORPTION BEHAVIOR OF MESOPOROUS TRANSITION METAL OXIDE TEMPLATED FROM SBA-15 AND KIT-6

2014 ◽  
Vol 28 (10) ◽  
pp. 1450037 ◽  
Author(s):  
HONGJING WU ◽  
LIUDING WANG ◽  
YIMING WANG
Keyword(s):  
Electron Microscope ◽  
Microwave Absorption ◽  
Absorption Characteristic ◽  
Chemical Compositions ◽  
X Ray Diffraction ◽  
Hard Template ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
X Ray ◽  
Transmission Electron

In this paper, we have synthesized meso-oxides (i.e., Co 3 O 4 and NiO ) by using mesoporous silica as hard template. The microstructures and chemical compositions of the corresponding meso-oxides were characterized by the Transmission electron microscope-selected area electron diffusion (TEM-SAED), X-ray diffraction (XRD), scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDS), respectively. And, their electromagnetic and microwave absorption properties were investigated in the frequency range of 2–18 GHz. The results indicate that meso-oxide templated from KIT-6 (i.e., meso-K– Co / Ni ) exhibit a dual absorption characteristic compared with those using SBA-15 as hard template. This phenomenon suggests that meso-oxides templated from SBA-15 and KIT-6 can exhibit different microwave absorption behaviors due to their respective microstructures.

Precipitate Structure in an Alumina Dispersion-Strengthened Copper Base Composite Layer

2010 ◽  
Vol 152-153 ◽  
pp. 634-638
Author(s):  
Bao Hong Tian ◽  
Xiao Hong Chen ◽  
Yi Zhang ◽  
Yong Liu
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Composite Layer ◽  
Lattice Parameter ◽  
Interface Structure ◽  
Parameter Mismatch ◽  
Direction Parallel ◽  
Transmission Electron ◽  
The Matrix ◽  
Α Al2o3

A dilute copper alloy of Cu-0.45wt%Al -0.066wt %Y was selected to fabricate nanometer size Al2O3 particles dispersion-hardened composite layer by using aluminizing-internal oxidation technique. The structure and size of the precipitate, interface structure, lattice parameter mismatch and morphology were investigated by means of high resolution transmission electron microscope, analytical transmission electron microscope and image processing by VEC software. Results show that two different size and structure nano-alumina precipitate were identified as α-Al2O3 and γ-Al2O3 respectively during different processing. The precipitates possess semi-coherence or coherence interface structure to matrix with typical loop-loop contrast. The cubic γ-Al2O3 precipitate in certain crystal plane and direction parallel to the matrix。

Investigations of Fine Grained Metallic Materials by Means of Orientation Maps in Transmission Electron Microscope

2012 ◽  
Vol 186 ◽  
pp. 53-57 ◽  
Author(s):  
Magdalena Bieda
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Quantitative Description ◽  
Ccd Camera ◽  
Microscopic Investigation ◽  
Automated System ◽  
Fine Grained ◽  
Transmission Electron ◽  
Orientation Maps ◽  
Diffraction Patterns

New subdivision of microscopic investigation called Orientation Microscopy (OM) is already well known in scanning electron microscope (SEM). Needs for investigation in nanoscale contribute to development of an appropriate method for transmission electron microscope (TEM). Automated acquisition and indexing of diffraction patterns, necessary for creation of orientation maps in TEM, cause more difficulties then in SEM. Nevertheless, the techniques of OM are also being developed in the Transmission Electron Microscope (TEM). Microdiffraction has been successfully introduced for creating such maps. Individual orientation measurements, which appeared in the convergent beam mode, can be used for quantitative description of microstructure of fine grained and deformed materials. The idea of the operation of the automated system in transmission electron microscope (TEM) which is developed in IMIM PAS relies on an automatic (with control position of the beam) acquisition of diffraction patterns using digital CCD camera, and indexing them, and then on the analysis of the set of individual crystallographic orientations. The graphic presentation of received sets of orientation can be analysed in order to obtain parameters and characteristics such as texture characteristics, characteristics of grain boundaries (based on orientation relationship) or the stereological characteristics. To illustrate application of this system, orientation maps measured in cold-rolled polycrystalline aluminium and its alloy 6013, and in multi-phase alloys of Fe-Cr-Co system after severe plastic deformation are presented.

Automatic Crystallographic Characterization in a Transmission Electron Microscope: Applications to Twinning Induced Plasticity Steels and Al Thin Films

2013 ◽  
Vol 19 (3) ◽  
pp. 693-697 ◽  
Author(s):  
M. Galceran ◽  
A. Albou ◽  
K. Renard ◽  
M. Coulombier ◽  
P.J. Jacques ◽  
...  
Keyword(s):  
Thin Films ◽  
Electron Microscope ◽  
Electron Diffraction ◽  
Transmission Electron Microscope ◽  
Microstructural Characterization ◽  
Fine Grained ◽  
Mapping Tool ◽  
Transmission Electron ◽  
Kikuchi Lines ◽  
Diffraction Patterns

AbstractA new automated crystallographic orientation mapping tool in a transmission electron microscope technique, which is based on pattern matching between every acquired electron diffraction pattern and precalculated templates, has been used for the microstructural characterization of nondeformed and deformed aluminum thin films and twinning-induced plasticity steels. The increased spatial resolution and the use of electron diffraction patterns rather than Kikuchi lines make this tool very appropriate to characterize fine grained and deformed microstructures.

Crystallographic Mapping in Scanning and Transmission Electron Micrsocopy with Application to Semiconductor Materials

1998 ◽  
Vol 523 ◽  
Author(s):  
D. J. Dingley ◽  
S. I. Wright ◽  
D. J. Dingley
Keyword(s):  
Electron Microscope ◽  
Electron Backscatter Diffraction ◽  
Orientation Imaging Microscopy ◽  
Lattice Parameter ◽  
Dark Field ◽  
Polycrystalline Materials ◽  
Orientation Imaging ◽  
Transmission Electron ◽  
Dark Field Microscopy ◽  
Backscatter Diffraction

AbstractThe two sister techniques, Electron Backscatter Diffraction and Orientation Imaging Microscopy which operate in a scanning electron microscope, are well established tools for the characterization of polycrystalline materials. Experiment has shown that the limiting resolution for mapping is the order of 0.1 microns. The basic techniques have been extended to include multiphase mapping. Whereas it has been possible to distinguish between phases of different crystal systems easily, it has not been possible to distinguish between phases that differ in lattice parameter by less than 5 %.An equivalent transmission electron microscope procedure has been developed. The technique couples standard hollow cone microscopy procedures with dark field microscopy. All possible dark field images that can be produced by tilting the electron beam are scanned to detect under what settings each crystal is brought into a diffracting condition. Subsequent analysis permits determination of both crystal phase and orientation.

scholarly journals Rapid Microwave Synthesis of β-SnWO4 Nanoparticles: An Efficient Anode Material for Lithium-Ion Batteries

2020 ◽  
Author(s):  
Sumedha N ◽  
Mabkhoot Alsaiari ◽  
Mohammed Jalalah ◽  
Shashank M ◽  
Fahad Alharthi ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Structural Parameters ◽  
Lithium Ion ◽  
High Specific Capacitance ◽  
Stoichiometric Ratio ◽  
X Ray ◽  
Transmission Electron ◽  
Adsorption Desorption ◽  
Charge Discharge

Abstract Here, we report a facile synthesis of β-SnWO4 nanoparticles via microwave heat treatment using SnCl2 and H2WO4, in the presence of tamarind seed powder. X-ray diffraction analysis confirmed the crystalline nature, revealing a cubic structure of β-SnWO4 nanoparticles. Morphological features were visualized using a scanning electron microscope which exhibited homogenously distributed clusters of nanoparticles which were further confirmed using transmission electron microscope. The micrographs also displayed some porosity. Energy dispersive X-ray spectroscopy confirmed the elemental contents such as tin, oxygen and tungsten in the same stoichiometric ratio as expected by the respective empirical formula. High-resolution transmission electron microscope was used to find the d-spacing which was ultimately used to analyze the structural parameters. The spectrum obtained using Fourier transform infrared spectroscopy illuminates different stretching vibrations. Additionally, Barrett-Joyner-Halenda analysis was carried out to investigate N2 adsorption-desorption isotherm as well as to govern the pore size distribution. Cyclic voltammetry measurements were implemented to analyze the ongoing electrode reactions throughout the charge/discharge for β-SnWO4 nanostructures. The galvanometric charge/discharge curves for β-SnWO4 have also been discussed. A high specific capacitance (600 mAhg-1 at 0.1 C) and excellent columbic efficiency (~100%) was achieved.

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