Sandeep Kumar; Neetu Ahlawat; Navneet Ahlawat
Abstract
In the present work, the results of microstructure, dielectric and ferroelectric investigation of microwave sintered CaCu3Ti4O12 (CCTO) ceramic with different heating rate are presented. Scanning electron micrographs revealed that grain size decreases from 1.167 µm to 0.744 µm with increased ...
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In the present work, the results of microstructure, dielectric and ferroelectric investigation of microwave sintered CaCu3Ti4O12 (CCTO) ceramic with different heating rate are presented. Scanning electron micrographs revealed that grain size decreases from 1.167 µm to 0.744 µm with increased heating rate from 10ºC/min. to 50ºC/min which can be explained on the basis of phenomenological kinetic equation for grain growth. Dielectric response also found to influence by heating rate. The CCTO ceramic sintered with 50 ºC/min. exhibited highest dielectric constant (ɛr~3915) with nominal losses (0.10) at room temperature in broad frequency range from 10 2 Hz-10 5 Hz. Cole-Cole plots revealed the change in grain boundary resistivity mainly caused by the oxygen vacancy activities and affected by varying sintering heating rate. An anomaly observed for 50 ºC/min heating rate due to trapping of oxygen at grain boundaries. The remnant polarization and coercive field for CCTO ceramic sintered with 50ºC/min were 0.1 µC /cm 2 and 1.477 kV /cm respectively. Remnant polarization found to decrease while the coercive field increases with increasing heating rate applying these are micro-structural dependent.
Sandeep Kumar; L. K. Sahay; Anal K. Jha; K. Prasad
Abstract
A low-cost, green and reproducible stearic acid assisted synthesis of nanocrystalline powder of (Ag0.5Fe0.5)TiO3 (n-AFT) is reported. X-ray, FTIR, energy dispersive X-ray and transmission electron microscopy analyses are performed to ascertain the formation of n-AFT. Rietveld refinement of X-ray data ...
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A low-cost, green and reproducible stearic acid assisted synthesis of nanocrystalline powder of (Ag0.5Fe0.5)TiO3 (n-AFT) is reported. X-ray, FTIR, energy dispersive X-ray and transmission electron microscopy analyses are performed to ascertain the formation of n-AFT. Rietveld refinement of X-ray data indicated the formation of a single-phase monoclinic structure. Individual nanoparticles almost spherical in shape having the sizes of 5-14 nm are found. The mechanism of nanotransformation for the soft-chemical synthesis of n-AFT has been explained using nucleation and growth theory. UV-visible study revealed the surface plasmon resonance at 318 nm. Dielectric study revealed a low value of dielectric constant (= 177) and dielectric loss (= 0.013) at 1 kHz. Magnetic studies have been carried out using vibration sample magnetometer, which indicated the possibility of magnetoelectric coupling.
Neeraj Dilbaghi; Harmanmeet Kaur; Ritesh Kumar; Pooja Arora; Sandeep Kumar
Abstract
Nanotechnology is an interdisciplinary science comprising of various disciplines such as physics, chemistry, electronics, material science, health science, biology and veterinary science. The ability to manufacture and manipulate material at nanoscale has offered opportunities to interface biological ...
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Nanotechnology is an interdisciplinary science comprising of various disciplines such as physics, chemistry, electronics, material science, health science, biology and veterinary science. The ability to manufacture and manipulate material at nanoscale has offered opportunities to interface biological systems with outer world in new ways and with unprecedented precision. Veterinary science deals with all non human animals including wildlife and domesticated animals, livestock, working animals and companion animals. Nanotechnology has contributed in revolutionizing health and veterinary sciences by providing new tools and new materials for molecular and cellular biology that are beneficial for living organisms. The variety of nanomaterials that are used for diagnosis and treatment include metallic nanoparticle, quantum dots, carbon nanotubes, magnetic nanoparticles, fullerenes, liposomes, dendrimers and engineered hybrid nanoparticles. However, at present, little data is available on the ecotoxicological and toxicological effects associated with these nanomaterials and hence there is a need to address these issues as physiological properties of nanomaterials are expected to influence their biological response. It is believed that in the upcoming years, nanotechnology will reform the science and technology of the animal health and will help to boost up the livestock production. Nanotechnology based techniques like bioanalytical nanosensors, nanofluidics, targeted drug delivery etc has the potential to solve problems related to diagnosis and treatment of diseases. In this review, we emphasize on how nanotechnology is swiftly changing the diagnosis and treatment patterns at faster and low cost in less time duration. There can be numerous applications of nanotechnology in disease diagnosis, treatment, drug delivery, animal nutrition, animal breeding, tissue engineering and animal identity verification. The role of nanotechnology in veterinary sciences is chiefly discussed as how nanomaterials can modernize the present life.
Ajay Shankar; Sandeep Kumar; Sanjeeve Thakur; Rajni Porwal; R. P. Pant
Abstract
Nanocrystalline NixCo1-xFe2O4 were synthesized and studied for their structural and magnetic properties. The effect of doping ion concentration on lattice parameter, crystallite size and the lattice strain pertaining to the ionic radii has been investigated. Electron microscopy supports the parameters ...
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Nanocrystalline NixCo1-xFe2O4 were synthesized and studied for their structural and magnetic properties. The effect of doping ion concentration on lattice parameter, crystallite size and the lattice strain pertaining to the ionic radii has been investigated. Electron microscopy supports the parameters and gives morphological view of the system. The magnetic measurement reveals the information on the effect of stoichiometry variation in existing superparamagnetism. Further, the spin dynamics and their role on dipolar interactions, extent of superexchange and spin-spin relaxation among nanoparticles have been investigated. Also, an attempt has been made to understand the UV irradiation effect on photosensitive Co 2+ ion on Ni ferrite by in-situ electron spin resonance measurements.
Sandeep Kumar; Neeraj Dilbaghi;Anju Manuja; Gaurav Bhanjana
Abstract
Nanoparticles are being designed with chemically modifiable surfaces to attach a variety of molecules to improve biosensing, imaging techniques, delivery vehicles, and other useful biological tools. Keeping this in view, the present research work is focused on investigation of cytotoxicity of metal oxide ...
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Nanoparticles are being designed with chemically modifiable surfaces to attach a variety of molecules to improve biosensing, imaging techniques, delivery vehicles, and other useful biological tools. Keeping this in view, the present research work is focused on investigation of cytotoxicity of metal oxide nanoparticles. Different metal oxide nanoparticles (e.g titanium dioxide, zinc oxide, iron oxide, aluminum oxide etc) of different sizes and different concentrations were used to investigate the cellular response. Electron microscopy and colorimetric assays were used to characterize the various process steps. Zirconium oxide nanoparticles were used in suspension form stabilized with stabilizer and the others were used as their aqueous suspension. Results clearly reflect that as the concentration increases, cytotoxicity also increases. As aggregation occurs, cytotoxicity decreases. In suspension with stabilizer, cytotoxicity is more as compared to aqueous suspensions.