Sampat Raj Vadera

Bio: Sampat Raj Vadera is an academic researcher from Indian Institute of Technology, Jodhpur. The author has contributed to research in topics: Nanoparticle & Ferrite (magnet). The author has an hindex of 26, co-authored 63 publications receiving 2242 citations. Previous affiliations of Sampat Raj Vadera include Andhra University.

Magnetic properties of nanocomposites of mixed oxides of iron and chromium synthesized under different oxidative environments

Abstract: Synthesis of nanocomposites of mixed oxides of Fe and Cr in a copolymer matrix of aniline and formaldehyde at room temperature along with IR, XRD and57Fe Mossbauer studies on as synthesized as well as the samples on heating at different temperatures is described. The XRD and57Fe Mossbauer studies show the formation of nanosized iron oxide particles. These studies further show the formation of nanosized particles of metal oxides and formation of solid solution of iron and chromium oxide on heating the samples at 700°C. Further, the IR studies show that the polymeric backbone is strongly influenced by different reaction conditions and lead to variable magnetic character in the heated samples as shown by their Mossbauer studies.

Development of simple chemical method for synthesis of single phase Ni-Zn ferrite nanopowders

Abstract: A precursor based method has been developed for the synthesis of nanostructured, single phase Ni–Zn ferrite powders (Ni1–xZnxFe2O4 with x=0·20, 0·35, 0·50 and 0·60). Precursor powders were synthesised by reacting aqueous solutions of metal nitrates and ethylene diamine tetraacetic acid and then evaporating them to dryness. The precursors were calcined in air for 2·30 h at different temperatures ranging from 250 to 450°C. The powders synthesised in this manner were characterised by using X-ray diffraction, thermogravimetric differential scanning calorimetric analysis, Brunauer–Emmett–Teller surface area measurement and SEM. Magnetic characterisation was performed by using a vibrating sample magnetometer. The method provides a simple and cost effective route to produce single phase, Ni–Zn ferrite nanopowders, with average crystallite size of ∼25 nm, at comparatively low temperature.

Preparation, Characterization and Properties of Flexible Magnetic Nanocomposites of NiFe2O4-polybenzoxazine-LLDPE

Abstract: A simple method for the preparation of magnetic nanocomposites consisting of NiFe2O4 nanoparticles, polybenzoxazine (PB), linear low-density polyethylene (LLDPE) and LLDPE-g- Maleic anhydride (LgM) is described. Composites were prepared by forming benzoxazine- NiFe2O4 nanocomposites followed by melt blending with LLDPE and thermal curing of benzoxazine. The composites were characterized by XRD, DSC and TGA, FT-IR, SEM, UTM and VSM. The saturation magnetization of the composites containing 33.25 wt% NiFe2O4 was 7.72 emu/g and it decreased with decreasing amount of NiFe2O4 in the composite. The composite films exhibited mechanical flexibility as well as magnetic properties.

Preparation of polybenzoxazine–Ni–Zn ferrite magnetic nanocomposite and its magnetic property

Abstract: The synthesis of a new type, high performance polybenzoxazine–ferrite nanocomposite has been reported. A simple aqueous solution based method was developed for preparation of several compositions of Ni1–xZnxFe2O4 (x=0.20–0.60) nanopowders using metal nitrates and EDTA. Benzoxazine monomer was prepared by employing a solvent less method using aniline, paraformaldehyde and bisphenol A as starting materials. Polybenzoxazine–ferrite nanocomposites were prepared by using a solvent casting method followed by thermal curing. The synthesised powders, monomer, polymer and the resultant composites were characterised by using thermogravimetric analysis and differential scanning calorimeter, surface area and pore size analyser, scanning electron microscope (SEM) and transmission electron microscope. X-ray diffraction spectra of the powders revealed the formation of single phase Ni–Zn ferrite, with average crystallite size of about 20–30 nm. Transmission electron microscopy micrographs confirmed the average f...

Synthesis of Various Ferrite (MFe₂O₄) Nanoparticles and Their Application as Efficient and Magnetically Separable Catalyst for Biginelli Reaction.

Abstract: Herein, we reports the application of various spinel ferrite nanoparticles, MFe2O4 (M = Co, Ni, Cu, Zn), as efficient catalyst for Biginelli reaction. All ferrite nanoparticles were synthesized using a novel aqueous solution based method. It was observed that, the catalytic activity of the ferrite nanoparticles followed the decreasing order of CoFe2O4 > CuFe2O4 > NiFe2O4 > ZnFe2O4. The most important feature of these ferrite nanocatalysts is that, these nanoparticles can directly be used as catalyst and no surface modification or functionalization is required. These ferrite nanoparticles are easily separable from reaction mixture after reaction by using a magnet externally. Easy synthesis methodology, high catalytic activity, easy magnetic separation and good reusability make these ferrite nanoparticles attractive catalysts for Biginelli reaction.

Graphene-Based Materials: Synthesis, Characterization, Properties, and Applications

Abstract: Graphene, a two-dimensional, single-layer sheet of sp(2) hybridized carbon atoms, has attracted tremendous attention and research interest, owing to its exceptional physical properties, such as high electronic conductivity, good thermal stability, and excellent mechanical strength. Other forms of graphene-related materials, including graphene oxide, reduced graphene oxide, and exfoliated graphite, have been reliably produced in large scale. The promising properties together with the ease of processibility and functionalization make graphene-based materials ideal candidates for incorporation into a variety of functional materials. Importantly, graphene and its derivatives have been explored in a wide range of applications, such as electronic and photonic devices, clean energy, and sensors. In this review, after a general introduction to graphene and its derivatives, the synthesis, characterization, properties, and applications of graphene-based materials are discussed.

Broadband and Tunable High‐Performance Microwave Absorption of an Ultralight and Highly Compressible Graphene Foam

Abstract: The broadband and tunable high-performance microwave absorption properties of an ultralight and highly compressible graphene foam (GF) are investigated. Simply via physical compression, the microwave absorption performance can be tuned. The qualified bandwidth coverage of 93.8% (60.5 GHz/64.5 GHz) is achieved for the GF under 90% compressive strain (1.0 mm thickness). This mainly because of the 3D conductive network.