Ceramic Composite
G. Upender; V. Chandra Mouli; V. Sreenivasulu; Praveena Kuruva; M. Prasad
Abstract
The new tellurite glasses with chemical composition 64TeO2-15CdO-(20-x) ZnO-xLi2O-1V2O5 (x= 0, 5, 10, 15 and 20 mol %) were synthesized by traditional melt quench hardening method. The glass samples showed broad humps of typical amorphous phase in the X- ray diffraction patterns. The physical properties ...
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The new tellurite glasses with chemical composition 64TeO2-15CdO-(20-x) ZnO-xLi2O-1V2O5 (x= 0, 5, 10, 15 and 20 mol %) were synthesized by traditional melt quench hardening method. The glass samples showed broad humps of typical amorphous phase in the X- ray diffraction patterns. The physical properties of glass samples such as density (ρ), molar volume (Vm), oxygen packing density (OPD), refractive index (n), molar refractivity (Rm) and metallization parameter (M) were estimated. The Fourier transform infrared spectroscopy (FTIR) studies exhibited that replacement of ZnO by Li2O forms significantly some basic structural units of TeO4, TeO3/TeO3+1 and ZnO4. Differential scanning calorimetry (DSC) was employed to find out the glass transition temperature (Tg) and thermal stability ( ). The optical enthrallment studies exhibited that the cut-off wavelength (λ) decreases while optical energy gap (Eopt) and Urbach energy ( ) values increases with an increase an escalation of Li2O content. This tellurite glasses possess an important use such as sensor devices, storage of data system and industrial applications etc.
A. K. Sahu; Priyambada Mallick; S. K. Satpathy; Banarji Behera
Abstract
Synthesis of polycrystalline samples of Bi1-xNdxFeO3 [x = 0.5, 0.6, 0.7 and 0.8] were demonstrated following solid-state reaction method at high temperature. The structural properties of the sample were confirmed through the X-ray diffraction technique. The dielectric study of the compounds was performed ...
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Synthesis of polycrystalline samples of Bi1-xNdxFeO3 [x = 0.5, 0.6, 0.7 and 0.8] were demonstrated following solid-state reaction method at high temperature. The structural properties of the sample were confirmed through the X-ray diffraction technique. The dielectric study of the compounds was performed at different frequencies in the range of 100 Hz – 10 6 Hz for various temperatures. The non-Debye type of relaxation process confirmed from impedance analysis. The materials showed a negative temperature coefficient of resistance (NTCR) behavior at various temperatures and frequencies. AC conductivity of the materials with frequency at different temperatures satisfied the universal power law of Johnscher. Thermistor constant (β), sensitivity factor (α), and stability factor for all the samples were calculated and confirmed the characteristics of NTC thermistor.
Khalid Sultan; Rubiya Samad; Feroz A. Najar; Shohaib Abass; Saima Jahan; Mudasir Rashid Rather; M. Ikram
Abstract
Polycrystalline bulk samples of chemical composition La1-xSrxVO4 (x = 0.0, 0.1, 0.3, 0.5) were prepared by solid state reaction method. The Morphology and structure wascharacterised by Scanning Electronic microscopy and powder X-ray diffraction respectively. All the prepared material were single-phase ...
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Polycrystalline bulk samples of chemical composition La1-xSrxVO4 (x = 0.0, 0.1, 0.3, 0.5) were prepared by solid state reaction method. The Morphology and structure wascharacterised by Scanning Electronic microscopy and powder X-ray diffraction respectively. All the prepared material were single-phase and co-doped ions were successfully incorporated in LaVO4 lattice. The EDAX spectrum shows that the percentage composition of given elements in the proposed formula was in good agreement with the corresponding values determined experimentally. The Raman spectra of LaVO4 reflect the VO4 type structure that consists of four different V–O bands. The prominent Raman band at about 860 cm -1 can be assigned to the symmetric V–O stretching mode while the weak Raman band at 792 cm -1 is assigned to antisymmetric V–O stretching mode. With increase in Sr doping, optical band gap was found to decrease resulting in increase in conductivity. The dielectric constant as well as dielectric loss shows a relaxor type of behaviour for higher doping concentration which can be attributed to the chemical pressure induced in LaVO4 with the doping of Sr ions. The studies performed on ac conductivity identifies that the conduction mechanism follows the charge hopping between localised states and follow the small polaron conduction.
M.B. Lava; Uday M. Muddapur; B. Nagaraj
Abstract
Biosynthesis of gold nanoparticles is one among the best and cheap economical viable process, which is environmental friendly. The purpose of this study is to synthesis the gold nanoparticles using Lobelia nicotianifolia leaf extract and to investigate its biological activities. The synthesized gold ...
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Biosynthesis of gold nanoparticles is one among the best and cheap economical viable process, which is environmental friendly. The purpose of this study is to synthesis the gold nanoparticles using Lobelia nicotianifolia leaf extract and to investigate its biological activities. The synthesized gold nanoparticles were characterized by UV-vis spectroscopy, TEM, SAED, FTIR and XRD, the nanoparticles produced at maximum absorbance 532 nm. The Characterization study proved that the size and shape of AuNPs were spherical in shape, with an average size of 80 nm. Synthesized AuNPs were evaluated for various in-vitro biological studies.
Savithri. M. Nampoothiri; Viji. C; E. M. Mohammed; Robin Francis
Abstract
Nickel ferrite (NiFe₂O₄) nanoparticles were synthesized using sol-gel method and the powdered samples were sintered at 100°C and 200°C. X-ray Diffraction (XRD) patterns were used to determine the structure of nickel ferrite nanoparticles. Obtained the lattice parameter from the XRD data and ...
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Nickel ferrite (NiFe₂O₄) nanoparticles were synthesized using sol-gel method and the powdered samples were sintered at 100°C and 200°C. X-ray Diffraction (XRD) patterns were used to determine the structure of nickel ferrite nanoparticles. Obtained the lattice parameter from the XRD data and calculated the particle size using Debye- Sherrer formula. The details of the surface morphology of NiFe2O4 nanoparticles were studied by Scanning Electron Microscopic (SEM) analysis. The work aims at the investigation of the dielectric properties such as dielectric loss and permittivity of Nickel ferrite nanoparticles at various frequencies and temperatures. In addition, the ac conductivity of the nickel ferrite nanoparticles was studied.
Nashiruddin Ahammed; M. Mehedi Hassan
Abstract
In this article, auto combustion prepared Ni1-xFexO (0≤x≤0.10) nanoparticles (NPs) have been investigated for their structural, morphological and optical properties. X-ray diffraction (XRD) studies reveal that all Fe doped NiO samples crystallize in single phase without any impurity. The crystallite ...
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In this article, auto combustion prepared Ni1-xFexO (0≤x≤0.10) nanoparticles (NPs) have been investigated for their structural, morphological and optical properties. X-ray diffraction (XRD) studies reveal that all Fe doped NiO samples crystallize in single phase without any impurity. The crystallite size monotonically decreases from 20 nm to 10 nm with increasing Fe substitution. Transmission Electron Microscope images represent that the synthesized NiO NPs with size around 28 nm. A red shift in UV-Vis spectra indicates that band gap can be tuned by Fe doping from 3.76 eV to 2.51 eV because of the upward shifting of t2g level. The broad transmittance peak in Fourier transform infra-red spectra at 500 cm -1 is assigned to Ni–O stretching vibration mode. Differential scanning calorimetry curve revealed that the transition at 250 o C was exothermic because of structural relaxation. Copyright © VBRI Press.
S. N. Sarangi; V. Siva; B. K. Padhi; P. K. Sahoo
Abstract
We report the fabrication and characterization of photosensitive heterostructure device using pure and Cu doped ZnO nanorods on n-Si substrate using a low cost hydrothermal technique. Special techniques like Rutherford backscattering spectroscopy and Proton Induced X-ray emission (PIXE) were used to ...
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We report the fabrication and characterization of photosensitive heterostructure device using pure and Cu doped ZnO nanorods on n-Si substrate using a low cost hydrothermal technique. Special techniques like Rutherford backscattering spectroscopy and Proton Induced X-ray emission (PIXE) were used to confirm the doping of Cu in ZnO nanorods. The PIXE measurements confirm the absence of any foreign element in parts per million level, except pure Cu doping in ZnO. The compressive stress in (002) peak develops after Cu doping is indicating the successful substitution of Cu +2 ions into Zn +2 lattice sites. The I-V measurement of 5% Cu doped ZnO device shows five orders of magnitude increase in current flow compared to 1% Cu doping. Under ultraviolet (UV) light exposure further enhancement of the photocurrent in the devices has been observed, which demonstrates the capability of Cu doped ZnO nanorods as a potential UV photodetector.
Swaroop Kumaraswamy; Gangadhar Babaladimath; Vishalakshi Badalamoole; Somashekarappa H Mallaiah
Abstract
In the present work, the synthesis of ZnO/PVA hydrogel nanocomposites was carried out using the gamma irradiation technique. The ZnO nanoparticles were synthesized using co-precipitation method and dispersed in the PVA solution. To prepare the ZnO/PVA hydrogel nanocomposites, the mixture was exposed ...
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In the present work, the synthesis of ZnO/PVA hydrogel nanocomposites was carried out using the gamma irradiation technique. The ZnO nanoparticles were synthesized using co-precipitation method and dispersed in the PVA solution. To prepare the ZnO/PVA hydrogel nanocomposites, the mixture was exposed to gamma irradiation dose of 25 kGy. The formation of ZnO nanoparticles in PVA matrix was confirmed using the powder X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), and the UV-Visible Spectrophotometer (UV). The surface morphology of the hydrogels was studied using the Field Emission Scanning Electron Microscopy (FESEM). The swelling ratio and equilibrium degree of swelling (% EDS) were evaluated and there was drastic reduction in swelling and % EDS with the addition of ZnO nanoparticles to the PVA mixture. The l-ascorbic acid was loaded to the hydrogels and the release data was monitored by the absorption wavelength at 252 nm using UV. The drug release data was fitted to zero order, first order, Higuchi’s model, and Korsmeyer-Peppas’s model for the detailed analysis. The results suggest that ascorbic acid release from the hydrogel matrix follows the non-Fickian mechanism.
V. Saikiran; N. Manikanthababu; N. Srinivasa Rao; S. V. S. Nageswara Rao; A. P. Pathak
Abstract
Trilayered HfO2/Ge/HfO2 thin films were grown on Si substrate by RF magnetron sputtering with HfO2 and Ge targets. The subsequent rapid thermal annealing (RTA) of these films at 700 & 800°C results in formation of Ge nanocrystals (NCs) in HfO2 matrix. X-ray diffraction (XRD) and micro-Raman spectroscopy ...
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Trilayered HfO2/Ge/HfO2 thin films were grown on Si substrate by RF magnetron sputtering with HfO2 and Ge targets. The subsequent rapid thermal annealing (RTA) of these films at 700 & 800°C results in formation of Ge nanocrystals (NCs) in HfO2 matrix. X-ray diffraction (XRD) and micro-Raman spectroscopy measurements were performed to confirm the formation of Ge NCs in the annealed samples. XRD results indicate that the as-deposited samples show amorphous behaviour, whereas the annealed samples clearly confirm the crystallinity of the films. The average size of the Ge NCs was found to increase with an increase in annealing temperature. Raman scattering studies confirm that the annealed samples exhibit a shift in peak position corresponding to Ge-Ge optical phonon vibrations, which clearly indicates the formation of Ge NCs. Conversely, as-deposited samples were also irradiated with swift heavy ions of 150 MeV Au and 80 MeV Ni at a fluence of 3×10 13 ions/cm 2 to synthesize Ge NCs. The structural properties of pristine and irradiated samples have been studied by using X-ray diffraction, Raman spectroscopy to substantiate the growth of Ge NCs upon irradiation. The results obtained by RTA are compared with the irradiated ones.
Baljinder Kaur; Lakhbir Singh; V. Annapu Reddy; Dae-Yong Jeong; Navneet Dabra; Jasbir S. Hundal
Abstract
Pure and Sr?doped bismuth ferrite Bi1-xSrx FeO3 (x = 0, 0.1, 0.2, 0.3) nanoparticles have been synthesized using combustion method. X- Ray diffraction study of these compounds confirms the rhombohedral structure with R3c space group. BiFeO3 peaks were observed at 2θ = 22.46o, 31.80o, 32.11o, 39.519o, ...
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Pure and Sr?doped bismuth ferrite Bi1-xSrx FeO3 (x = 0, 0.1, 0.2, 0.3) nanoparticles have been synthesized using combustion method. X- Ray diffraction study of these compounds confirms the rhombohedral structure with R3c space group. BiFeO3 peaks were observed at 2θ = 22.46o, 31.80o, 32.11o, 39.519o, 45.79o, 51.35o, 56.98o and 57.16o having miller indices as (012), (104), (110), (202), (024), (116), (214) respectively. The traces of secondary phase also appear along with desired phase of Sr?doped bismuth ferrite Bi1-xSrxFeO3 samples. The scanning electron microscopy of fractured pellets of the samples reveals the decrease in grain size with increase of Sr doping in Bi1-xSrxFeO3. Magnetic studies were carried out at room temperature up to a field of 10 kOe. M-H hysteresis loops showed a significant increase in magnetization with Sr substitution in BiFeO3. Compared to weak magnetisation with magnetizing field (M-H) shown by BiFeO3 nanoparticles (Remnant magnetization, Mr ~ 0.4x10-3 emu/g and coercive field, Hc ~ 0.065 kOe respectively), a significant enhancement in M-H loop was observed in Bi1-xSrx FeO3 compounds. The value of Mr ~ 0.525 emu/g and Hc ~ 3.70 kOe have been found to be maximum for x = 0.30 in Bi1-xSrx FeO3 compounds. Leakage current studies showed decrease in leakage current density of doped samples to that of pure BiFeO3 and x = 0.10 gives minimum value of 4.78 x 10-6 A/cm2 at 350 V/cm. The ferroelectric nature was confirmed by observed P-E loops in all the samples.
K. Kaviyarasu; M. Jayachandran; M. Maaza; E. Manikandan; J. Kennedy
Abstract
The electronics industry is heavily reliant on the use of silicon in devices ranging from solar panels to circuitry. This is of growing concern due to the environmental impact of sourcing and refining the material. Thus, a green source of silicon is of vital importance to meet the growing demand for ...
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The electronics industry is heavily reliant on the use of silicon in devices ranging from solar panels to circuitry. This is of growing concern due to the environmental impact of sourcing and refining the material. Thus, a green source of silicon is of vital importance to meet the growing demand for silicon in the industry. Rice husk represents an abundant source of nano silica. Currently the husk is considered a waste product that is separated from the grain during the milling process. Several methods have been trailed to extract the nano silica from rice husk. This paper reviews these current methods and presents suggestions of innovative research directions for processing techniques. This work reveals that the structural nature of superfine silica from rice husk ash is independent of the purification method, but dependent on the incineration temperature used. The paper concludes by advocating the physic-chemical process for producing high purity reactive nanosilica from rice husk. This method has the advantage of having high volume production versatility and being environmentally friendly. However, control of the morphology, shape, size, crystalline structure and chemical composition of rice husk nanostructures remains a challenge in the development of 3D nanopores arrays controllable by synthesis methods. We hope this article can provide the reader with snapshots of the recent development and future challenges.
Abdul Rauf Khaskheli; Saba Naz; Razium Ali Soomro; Faruk Ozul; Abdalaziz Aljabour; Nazar Hussain Kalwar; Abdul Waheed Mahesar; Imren Hatay Patir; Mustafa Ersoz
Abstract
This report demonstrates a facile and green fabrication method for the nickel nanoparticles using L-lysine as an efficient protecting agent. The application of green amino acid (L-lysine) enabled formation highly spherical and well-dispersed nanoparticles with average diameter in the range of 10 ±2.5 ...
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This report demonstrates a facile and green fabrication method for the nickel nanoparticles using L-lysine as an efficient protecting agent. The application of green amino acid (L-lysine) enabled formation highly spherical and well-dispersed nanoparticles with average diameter in the range of 10 ±2.5 nm. UV-Vis spectroscopy was used as a primary tool to elaborately study and optimize the necessary experimental condition for the developed synthetic protocol. Fourier transform infrared spectroscopy (FTIR) was used to confirm the surface protection of Ni NPs via L-lysine molecules whereas; atomic force microscopy (AFM) and scanning electron microscopy (SEM) provided morphological and topographical view of the as-synthesized Ni NPs. In addition, small angle X-ray scattering (SAXS) and X-ray diffraction (XRD) were used to evaluate compositional characteristics of fabricated L-lysine protected Ni NPs. The as-synthesized Ni NPs demonstrated excellent catalytic potential when utilized as heterogeneous catalyst for reduction of methylene Blue (MB) in the presence of sodium borohydride (NaBH4). The observed catalytic reaction was determined to follow pseudo first order kinetics with rate constant (K) and turn over frequency (TOF) determined to be 0.0224 and TOF value of 0.00411 s -1 respectively.
Suresh Sagadevan; Jiban Podder;Isha Das
Abstract
Lead selenide (PbSe) thin films were processed by chemical bath deposition (CBD) technique. To analyze the structure and the crystallite size of PbSe thin film X-ray diffraction (XRD) analysis was used. Using Scanning Electron Microscopy (SEM) the surface examination of the film was conducted. With the ...
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Lead selenide (PbSe) thin films were processed by chemical bath deposition (CBD) technique. To analyze the structure and the crystallite size of PbSe thin film X-ray diffraction (XRD) analysis was used. Using Scanning Electron Microscopy (SEM) the surface examination of the film was conducted. With the help of UV-visible absorption spectrum investigation of the optical properties were held. All the optical constants were determined from UV-visible absorption spectrum. The dielectric examination of PbSe thin films were analyzed for various frequencies and various temperatures. The AC electrical conductivity analysis brought to light that the conduction depended on both the frequency and the temperature. Photoconductivity analysis was carried out to the PbSe thin films.
Amrita Das; Vishal Shama
Abstract
In the present study, we investigate upon the synthesis and characterization of inorganic Eu 3+ doped Al2O3 nanophosphor for its structural and luminescent properties. The luminescent nanopowder was prepared using a combustion method in which the stoichiometric ratio of oxidizers and fuel was fixed to ...
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In the present study, we investigate upon the synthesis and characterization of inorganic Eu 3+ doped Al2O3 nanophosphor for its structural and luminescent properties. The luminescent nanopowder was prepared using a combustion method in which the stoichiometric ratio of oxidizers and fuel was fixed to one, with varying concentration of Eu 3+ ions acting as an activator. The prepared powder showed excellent thermal stability. For the identification of the phase and structure of the powder synthesized, X-ray diffractometer was used. From the XRD analysis, it is revealed that the rhombohedral crystallite phase of α-alumina was formed. The type of morphology and particle size was ascertained by Filed Emission-Scanning Electron Microscope (FE-SEM) and it was found that particles were having irregular spherical shape. A qualitative analysis of these nanophosphor particles was made using an Energy dispersive X-ray detector (EDS) and it was found that the samples were composed of Al, O and Eu ions. Photo-luminescence (PL) spectra were obtained using Spectrofluorometer absorption. The intense band position was observed at 618 nm and other less intense bands were also seen at 592 nm, 601 nm, 631 nm, while two weak bands were observed at 660 nm and 718 nm, when excited at 226 nm. The CIE color space chromaticity diagram was calculated from the CIE Calculator program using obtained PL spectra. The prepared nanophosphor powder was tested for latent fingerprint detection in forensic applications. The synthesized nanophosphor was successfully used as a latent fingerprint developing powder on various non-porous surfaces for forensic application.
Aditya Sharma; Shalendra Kumar;Hyun-Joon Shin; Mayora Varshney; Sejun Kang; Jaeyoon Baik; Tae-Kyun Ha; Keun-Hwa Chae
Abstract
ZrO2 and HfO2 powder samples were prepared by using the chemical precipitation method and subsequent annealing. Crystal structure, local electronic structure and dielectric constant of amorphous and crystalline powders of ZrO2 and HfO2 have been examined using the synchrotron X-ray diffraction, O K-edge ...
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ZrO2 and HfO2 powder samples were prepared by using the chemical precipitation method and subsequent annealing. Crystal structure, local electronic structure and dielectric constant of amorphous and crystalline powders of ZrO2 and HfO2 have been examined using the synchrotron X-ray diffraction, O K-edge X-ray absorption spectroscopy, Zr 3d and Hf 4f core-level X-ray photoelectron spectroscopy and temperature dependent dielectric measurements, respectively. Amorphous ZrO2 and HfO2 powders exhibit a local tetragonal structure, with mixed +3 and +4 valence states of Zr and Hf ions, and demonstrated the high dielectric performance. After the heat treatment, the tetragonal phase transforms into the monoclinic phase with dominant +4 valence state of Zr and Hf ions and the larger sized ZrO2 and HfO2 nanoparticles exhibited low dielectric constant. The manifestation of high dielectric constants in the amorphous ZrO2 and HfO2 samples is because of the hopping of electrons between the Zr +3 -Zr +4 and Hf +3 -Hf +4 networks.
R. Madhu Kumar; B. Lakshmeesha Rao; S. Asha; B. Narayana; K. Byrappa; Youjiang Wang; Donggang Yao; Y. Sangappa
Abstract
Silver nanoparticles (AgNPs) were synthesized in situ under gamma radiation environment at room temperature using aqueous silk fibroin (SF) solution obtained from Bombyx mori silk. The formation of the Ag NPs was confirmed by its characteristic surface plasmon resonance (SPR) band at around 424 nm in ...
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Silver nanoparticles (AgNPs) were synthesized in situ under gamma radiation environment at room temperature using aqueous silk fibroin (SF) solution obtained from Bombyx mori silk. The formation of the Ag NPs was confirmed by its characteristic surface plasmon resonance (SPR) band at around 424 nm in UV-visible spectra. The strength of the photoluminescence (PL) spectra decreases with increasing dosage reveals the optimum dose required for the synthesis of silver nanoparticles. Dynamic light scattering (DLS) measurement indicated the dose dependent size of the Ag NPs formed in the solution. The transmission electron microscopy (TEM) images showed that the formed nanoparticles are roughly spherical in shape. Further the X-ray diffraction (XRD) analysis confirms the nanocrystalline phase of silver with FCC crystal structure. From this study, it was found that the increasing the radiation dose increases the rate of reduction and decreases the particle size. The size of the Ag NPs can be tuned by controlling the radiation dose.
Manjusha and K. L. Yadav; Manjusha;K. L. Yadav
Abstract
Mixed spinel -perovskite composites of (x) Co0.5Ni0.5Fe2O4-(1−x) Bi0.9La0.1FeO3(x = 0, 0.25, 0.40, 0.55, 1.0) have been synthesized by conventional solid state reaction method and annealed at 850 ºC. The X-ray diffraction (XRD) pattern shows that the composites consisted of spinel Co0.5Ni0.5Fe2O4 ...
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Mixed spinel -perovskite composites of (x) Co0.5Ni0.5Fe2O4-(1−x) Bi0.9La0.1FeO3(x = 0, 0.25, 0.40, 0.55, 1.0) have been synthesized by conventional solid state reaction method and annealed at 850 ºC. The X-ray diffraction (XRD) pattern shows that the composites consisted of spinel Co0.5Ni0.5Fe2O4 and rhombohedral perovskite Bi0.9La0.1FeO3 ceramics. FESEM micrographs show closely packed microstructure with grain size in the range 503 nm - 960 nm. Variation of dielectric constant and dielectric loss with temperature at two fixed frequencies (500 kHz and 1 MHz) was studied. The composite with composition x = 0.55/sintered at 850 ºC exhibits the largest coercitivity (Hc) of 883 Oe. The saturation magnetization (Ms) and magnetic moment (µB) increase with an increase of Co0.5Ni0.5Fe2O4 concentration in the composites. From ferroelectric hysteresis loop analysis the values of remnant polarization (Pr) and coercive field (Ec) was found to lie in the range of 0.018-0.745 µC/cm 2 and 3.89-6.06 kV/cm. The relative change of magnetocapacitance was found to be 6.6% at a magnetic field of 8 kOe for x = 0.55 composition. Impedance analysis suggests the presence of a temperature dependent electrical relaxation in the material having a typical negative temperature coefficient of the resistance (NTCR) behavior analogous to a semiconductor.
K.M.K. Srivatsa; Preetam Singh; Sourav Das
Abstract
Considerable attention has been gained on the deposition of CeO2 thin films with (200) single orientation as hetero-epitaxial buffer layer on (200) oriented biaxially textured flexible Ni substrates, in the fabrication of superconductor and semiconducting epitaxial thin films for device applications. ...
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Considerable attention has been gained on the deposition of CeO2 thin films with (200) single orientation as hetero-epitaxial buffer layer on (200) oriented biaxially textured flexible Ni substrates, in the fabrication of superconductor and semiconducting epitaxial thin films for device applications. In this work we have deposited (200) oriented CeO2 thin films on biaxially textured Ni-W substrate in a single-step process by RF magnetron sputtering, using CeO2 target. X-ray diffraction analysis shows that for the CeO2 thin film deposited at RF sputtering power below 200 W and for the substrate temperature of 700 o C, the film assumes single (200) orientation. For the substrate temperature below 700 o C and RF sputtering powers above 200 W the film shows polycrystalline nature with (111) and (200) orientations. The Raman spectrum of single oriented (200) CeO2 thin film shows only one sharp peak at about 464 cm -1 corresponds to the presence of F2g mode of CeO2. The ellipsometry studies reveal the value refractive index and optical band gap of single oriented film as 2.52 and 3.41 eV, respectively.
N. S. Kokode; V. R. Panse; S. J. Dhoble
Abstract
In present work we studied the luminescence properties of Tb 3+ and Mn 2+ doped Ca2PO4Cl phosphor synthesized by wet chemical method were studied with extra heat treatment, to understand the mechanism of excitation and the corresponding emission of prepared phosphor. For the green emission, Tb 3+ ion ...
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In present work we studied the luminescence properties of Tb 3+ and Mn 2+ doped Ca2PO4Cl phosphor synthesized by wet chemical method were studied with extra heat treatment, to understand the mechanism of excitation and the corresponding emission of prepared phosphor. For the green emission, Tb 3+ ion is used as an activator, the excitation and emission spectra indicate that this phosphor can be effectively excited by 380 nm, to exhibit bright green emission centered at 545 nm corresponding to the f→f transition of Tb 3+ ions. The emission spectrum of Mn 2+ ion at 405 nm excitation 4 T1(4G) - 6 A1(6S) gives an emission band at 591 nm (orange-red). The observed photoluminescence (PL) measurements of Tb 3+ and Mn 2+ activated prepared phosphor indicates that these are the outstanding green and orange-red emitting potential phosphor , suitable application for the solid state lighting. The synthesized phosphors were analyzed by X-ray diffraction (XRD) for confirmation of phase and purity. The morphology and structure were characterized by scanning electron microscopy. Thus the phosphors in this system may be chosen as the green component for the tri-color lamp and certainly applied in w-UV LEDs. In the view of the excitation band and excellent luminescent properties, Ca2PO4Cl:Tb 3+ and Mn 2+ phosphor is expected to be a potential candidate for application in n-UV white LEDs and solid-state lighting because of its cost-efficient manufacturing, mercury-free excitation and eco-friendly characteristics.
N.J. Shivaramu; B.N. Lakshminarasappa; K.R. Nagabhushana; Fouran Singh
Abstract
Nanocrystalline erbium doped yttrium oxide (Y2O3:Er 3+ ) was synthesized by the sol-gel technique using citric acid as complexing agent. The synthesized samples were characterized by X-ray diffraction (XRD), Field emission scanning electron microscope (FE-SEM) techniques for phase-purity and microstructure. ...
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Nanocrystalline erbium doped yttrium oxide (Y2O3:Er 3+ ) was synthesized by the sol-gel technique using citric acid as complexing agent. The synthesized samples were characterized by X-ray diffraction (XRD), Field emission scanning electron microscope (FE-SEM) techniques for phase-purity and microstructure. Er 3+ doped Y2O3 crystallizes in cubic phase with an average crystallite size of 24.3 nm. The pellets of Y2O3:Er 3+ were irradiated with 100 MeV swift Si 8+ ions with fluence in the range of 3×10 11 - 3×10 13 ions cm -2 . Three well resolved thermoluminescence (TL) glows with peaks at ~422, 525 and 620 K were observed in Er 3+ doped Y2O3 samples. It was observed that the TL intensity was found to increases with increasing Er 3+ concentration up to 0.4 mol% in Y2O3 and thereafter it decreases with further increase of Er 3+ concentration. Also, the intensity of low temperature TL glow peak (~422 K) increases with increasing ion fluence up to 1×10 12 ions cm -2 and decreases with further increase of ion fluences. The TL trap parameters were calculated by glow curve shape method and the deconvoluted glows were exhibit of second order kinetics.
P.K. Mochahari; Ananta Rajbongshi; Nava Choudhury; F. Singh; K.C. Sarma
Abstract
Cadmium sulphide (CdS) nanostructured films were prepared by chemical bath deposition (CBD) method at room temperature. The prepared films were subjected to swift heavy ion (SHI) irradiation by using 100 MeV Si 8+ ion beams at various fluences from 1x10 11 to 1x10 13 ions/cm 2 . Structural, morphological, ...
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Cadmium sulphide (CdS) nanostructured films were prepared by chemical bath deposition (CBD) method at room temperature. The prepared films were subjected to swift heavy ion (SHI) irradiation by using 100 MeV Si 8+ ion beams at various fluences from 1x10 11 to 1x10 13 ions/cm 2 . Structural, morphological, optical properties of the pristine and irradiated films were characterized by X-ray diffractrometer (XRD), high resolution transmission electron microscope (HRTEM), UV-Vis spectroscopy and Raman spectroscopy. XRD study confirms the formation of nanocrystalline cubic phase in all the films. The crystallite size is found to increase from 7nm to 9 nm and shift of peak positions are observed due to irradiation. The lattice strain and dislocation density of the samples are of the order of 10 -3 and 10 16 m -2 respectively and the values are found to decrease upon irradiation. HRTEM images show that the shapes of the particles are nearly spherical and the selected area electron diffraction (SAED) pattern of HRTEM have also supported the formation of cubic phase CdS. The optical absorption spectra exhibit shift in the fundamental absorption edge and the optical band gap decreases from 2.585eV to 2.513 upon SHI irradiation. Three intense Raman lines for pristine as well as irradiated CdS have been observed and all the samples show shift in Raman lines relative to bulk CdS due to phonon localization. The SHI irradiation on chemically deposited CdS films is an important tool used for modification of structural, morphological and optical properties of the films for possible applications in device fabrication.
Brajesh Kumar; Kumari Smita; Luis Cumbal; Alexis Debut; Javier Camacho; Elisabeth Hernández-Gallegos; María de Guadalupe Chávez-López; Marcelo Grijalva; Yolanda Angulo; Gustavo Rosero
Abstract
Silver nanoparticles (AgNPs) have been synthesized via the green pomosynthetic procedure, using Passiflora tripartita var. mollissima fruit pigments as both the reducing and stabilizing agents. UV–Vis Spectroscopy, Dynamic Light Scattering, Transmission Electron Microscopy with Selected Area Electron ...
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Silver nanoparticles (AgNPs) have been synthesized via the green pomosynthetic procedure, using Passiflora tripartita var. mollissima fruit pigments as both the reducing and stabilizing agents. UV–Vis Spectroscopy, Dynamic Light Scattering, Transmission Electron Microscopy with Selected Area Electron Diffraction and Powder X-Ray Diffraction are used to completely characterize the AgNPs. The prepared AgNPs are found to be mostly spherical shapes with an average diameter of 49.7 ± 24.6 nm at room temperature. XRD analysis revealed the face-centered cubic geometry of AgNPs whereas Infrared spectrum and cyclic voltammetry measurements hypothesize the possible biomolecules (flavonoid C & O-glycosides) responsible for stabilization of the AgNPs. Synthesized AgNPs shows significant antioxidant efficacy (67%, 0.15 mM) against 1, 1-diphenyl-2- picrylhydrazyl. The AgNPs (0.01 – 20 μΜ) did not affect cell proliferation of the human cancer cell lines A -549 and HeLa, from lung and cervix, respectively. The use of environmentally benign, cost-effective and renewable materials like P. tripartita extract offers numerous benefits of eco-friendliness and compatibility for potential future pharmaceutical and biomedical applications.
Mayank Pandey; Girish M. Joshi; Kalim Deshmukh; Jamil Ahmad
Abstract
Polyvinyl alcohol (PVA) and Polyvinyl Pyrrolidone (PVP) based polymer electrolytes for different loading wt% of CdCl2 were prepared by solution casting. The structural complexation was confirmed and interlayer spacing (d) was evaluated by using X-ray diffraction (XRD) study. The chemical bonding between ...
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Polyvinyl alcohol (PVA) and Polyvinyl Pyrrolidone (PVP) based polymer electrolytes for different loading wt% of CdCl2 were prepared by solution casting. The structural complexation was confirmed and interlayer spacing (d) was evaluated by using X-ray diffraction (XRD) study. The chemical bonding between polymer and salt was identified by using Fourier transform infrared spectroscopy (FTIR) technique. The FTIR peak at 3402.43 cm -1 in addition of PVP in PVA/CdCl2 composite demonstrates the grafting between two polymers. The presence of ionic bright channels and variation in morphology for different loading wt% of CdCl2 was confirmed by scanning electron microscope (SEM) and was also verified by Atomic force microscopy (AFM) micrographs. The analysis of impedance spectroscopy represented by semicircular pattern is driven by conduction mechanism and correlated with electrical conductivity. The enhanced AC conductivity of polymer electrolyte is directly proportional to frequency (50Hz-1MHz). The maximum value of DC conductivity 1.65x10 -5 S/m evaluated from Arrhenius plots and attribute to high mobility of free charges at higher temperature. The evaluated results of structural, morphological and electrical properties of present composites make the present research good for electrochemical devices.
D. M. Pimpalshende; S. J. Dhoble
Abstract
Nowadays the research on synthesis of inorganic luminescent material with proper dimensions and morphologies has attracted great attention. Inorganic luminescent materials like LaPO4 have found many practical applications in the field of electroluminescent devices, integrated optics, biological labels, ...
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Nowadays the research on synthesis of inorganic luminescent material with proper dimensions and morphologies has attracted great attention. Inorganic luminescent materials like LaPO4 have found many practical applications in the field of electroluminescent devices, integrated optics, biological labels, modern lighting and display fields. We have prepared Dysprosium (Dy) doped LaPO4 nanoparticles at relatively low temperature in polyethylene glycol (PEG) medium by wet chemical method. Dy 3+ is doped in LaPO4 at various atomic concentrations (1, 2, 5 and 10 at %). All the samples have been characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), photoluminescence (PL) and thermoluminescence (TL) techniques. XRD study reveals the monoclinic structure of prepared nanoparticles. Unit cell volume is found to be decrease linearly with increasing Dy 3+ concentration indicating homogeneous substitution of La 3+ ions in LaPO4 by Dy 3+ . From the FTIR study it is found that the band at 1044 cm -1 assigned to the phosphate group PO4 3- in the region of υ3 anti-symmetric stretching of P-O band. The PL spectrum shows emission band at about 435 nm is observed due to the transision of Dy 3+ ions corresponding to wavelength in the blue color region. The glow curve of LaPO4: Dy phosphor obeys second order kinetics.
Niyaz Parvin Shaik; N. V. Poornachandra Rao; K. V. R. Murthy
Abstract
Pure LaPO4 and LaPO4: Eu (0.5 mol %) Ce (0.5 mol %) phosphors were synthesized by the solid-state reaction method. X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), photoluminescence (PL) spectra and the particle size analysis were used to characterize ...
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Pure LaPO4 and LaPO4: Eu (0.5 mol %) Ce (0.5 mol %) phosphors were synthesized by the solid-state reaction method. X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), photoluminescence (PL) spectra and the particle size analysis were used to characterize these samples. The XRD results reveal that the synthesized LaPO4:Eu (0.5 mol%) Ce (0.5 mol%) phosphors are well crystalline and assigned to the monoclinic structure with a main (120) diffraction peak. The calculated crystallite size of pure LaPO4 and LaPO4:Eu, Ce phosphors were 67.6nm and 64nm respectively. Upon excitation at 254nm wavelength, the emission spectrum of pure LaPO4 phosphor emits a maximum intensity peak at 470 (blue) nm. In the emission spectrum of LaPO4:Eu 3+ Ce 3+ phosphor, the low contributions of the red (613nm) 5D0-7F2 emissions and the high intensity of the orange-red (589nm)5D0-7F1 emission results in high color purities.The most intense emissions appearing in the 580-620nm region is responsible for the strong orange-red luminescence observed in the Eu,Ce doped LaPO4 phosphor whose CIE colour coordinates are x = 0.57 and y = 0.43.Thus the prepared phosphors can be used as an orange-red emitting material in the field of illuminations and display devices.
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