Author
Shakeel Khan
Bio: Shakeel Khan is an academic researcher from Aligarh Muslim University. The author has contributed to research in topics: Dielectric & Crystallite. The author has an hindex of 16, co-authored 74 publications receiving 859 citations.
Papers published on a yearly basis
Papers
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TL;DR: In this paper, the structural, electrical, and magnetic properties of CoFe2O4 and CoIn0.15Fe1.85O4 ferrites were analyzed using X-ray diffraction and Raman spectroscopy to confirm the formation of single phase cubic spinel structure.
Abstract: Nanoparticles of CoFe2O4 and CoIn0.15Fe1.85O4 ferrites were prepared by citrate gel route and characterized to understand their structural, electrical, and magnetic properties. X-ray diffraction and Raman spectroscopy were used to confirm the formation of single phase cubic spinel structure. The average grain sizes from the Scherrer formula were below 50 nm. Microstructural features were obtained by scanning electron microscope and compositional analysis by energy dispersive spectroscopy. The hysteresis curve shows enhancement in coercivity while reduction in saturation magnetization with the substitution of In3+ ions. Enhancement of coercivity is attributed to the transition from multidomain to single domain nature. Electrical properties, such as dc resistivity as a function of temperature and ac conductivity as a function of frequency and temperature were studied for both the samples. The activation energy derived from the Arrhenius equation was found to increase in the doped sample. The dielectric cons...
235 citations
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TL;DR: In this paper, the structural and optical properties of synthesized samples were studied by using X-ray diffraction (XRD), field scanning electron microscopy (FESEM), Fourier transform infrared (FTIR) spectroscopy, UV-Vis spectroglobalization and Raman Spectroscopy.
99 citations
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TL;DR: In this paper, Nanocrystalline pure and doped Sn 1-x Mn x O 2 samples were synthesized chemically using co-precipitation technique and FTIR spectra were recorded to reveal the functional groups in as-synthesized powder samples.
73 citations
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TL;DR: In this article, the structural properties and surface morphology of SnO 2 were studied using x-ray diffractometer (XRD) and scanning electron microscopy (SEM) respectively.
70 citations
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TL;DR: In this paper, structural, electrical and optical properties of Co substituted manganese ferrite of the composition Mn1−xCoxFe2O4 (x = 0.0, 0.1,0.2, 0 3, 0 4, 0 5) synthesized by sol-gel technique are reported.
Abstract: We report the structural, electrical and optical properties of Co substituted manganese ferrite of the composition Mn1−xCoxFe2O4 (x = 0.0, 0.1, 0.2, 0.3, 0.4, 0.5) synthesized by sol-gel technique. X-ray diffraction (XRD) patterns confirm the formation of single-phase cubic spinel structure. The average crystallite size of these materials is found to be in the range of 20–35 nm and lattice constant is found to decrease as Co2+ concentration is increased. The permittivity (ɛ), dielectric loss (tanδ) and ac conductivity ( σ ac ) have been determined at room temperature as a function of frequency (42 Hz to 5 MHz). The results of dielectric properties indicate the normal Maxwell-Wagner type dielectric dispersion due to interfacial polarization. DC electrical resistivity has been performed using two probe technique. The decrease of resistivity with temperature confirms the semiconducting nature of the samples. Real and imaginary part of impedance ( Zʹ and Zʺ) suggest existence of one relaxation mechanism which is attributed to the co-effect of grains and grain boundaries. The energy band gap as determined from the UV–visible spectra decreases gradually with the Co increasing content.
66 citations
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TL;DR: A biosensor is an integrated receptor-transducer device, which can convert a biological response into an electrical signal as mentioned in this paper, which can transform biological signals into electrochemical, electrical, optical, gravimetric, or acoustic signals.
Abstract: A biosensor is an integrated receptor-transducer device, which can convert a biological response into an electrical signal The design and development of biosensors have taken a center stage for researchers or scientists in the recent decade owing to the wide range of biosensor applications, such as health care and disease diagnosis, environmental monitoring, water and food quality monitoring, and drug delivery The main challenges involved in the biosensor progress are (i) the efficient capturing of biorecognition signals and the transformation of these signals into electrochemical, electrical, optical, gravimetric, or acoustic signals (transduction process), (ii) enhancing transducer performance ie, increasing sensitivity, shorter response time, reproducibility, and low detection limits even to detect individual molecules, and (iii) miniaturization of the biosensing devices using micro-and nano-fabrication technologies Those challenges can be met through the integration of sensing technology with nanomaterials, which range from zero- to three-dimensional, possessing a high surface-to-volume ratio, good conductivities, shock-bearing abilities, and color tunability Nanomaterials (NMs) employed in the fabrication and nanobiosensors include nanoparticles (NPs) (high stability and high carrier capacity), nanowires (NWs) and nanorods (NRs) (capable of high detection sensitivity), carbon nanotubes (CNTs) (large surface area, high electrical and thermal conductivity), and quantum dots (QDs) (color tunability) Furthermore, these nanomaterials can themselves act as transduction elements This review summarizes the evolution of biosensors, the types of biosensors based on their receptors, transducers, and modern approaches employed in biosensors using nanomaterials such as NPs (eg, noble metal NPs and metal oxide NPs), NWs, NRs, CNTs, QDs, and dendrimers and their recent advancement in biosensing technology with the expansion of nanotechnology
401 citations
12 Aug 2016
TL;DR: In this article, the authors proposed a hybrid threshold adaptable quantum secret sharing scheme, using an m-bonacci orbital angular momentum (OAM) pump, Lagrange interpolation polynomials, and reverse Huffman-Fibonacci-tree coding.
Abstract: With prevalent attacks in communication, sharing a secret between communicating parties is an ongoing challenge. Moreover, it is important to integrate quantum solutions with classical secret sharing schemes with low computational cost for the real world use. This paper proposes a novel hybrid threshold adaptable quantum secret sharing scheme, using an m-bonacci orbital angular momentum (OAM) pump, Lagrange interpolation polynomials, and reverse Huffman-Fibonacci-tree coding. To be exact, we employ entangled states prepared by m -bonacci sequences to detect eavesdropping. Meanwhile, we encode m -bonacci sequences in Lagrange interpolation polynomials to generate the shares of a secret with reverse Huffman-Fibonacci-tree coding. The advantages of the proposed scheme is that it can detect eavesdropping without joint quantum operations, and permits secret sharing for an arbitrary but no less than threshold-value number of classical participants with much lower bandwidth. Also, in comparison with existing quantum secret sharing schemes, it still works when there are dynamic changes, such as the unavailability of some quantum channel, the arrival of new participants and the departure of participants. Finally, we provide security analysis of the new hybrid quantum secret sharing scheme and discuss its useful features for modern applications.
400 citations
01 Jan 1996
TL;DR: Ahn et al. as discussed by the authors studied the effect of Fe doping on the Mn site in the ferromagnetic and antiferromagnetic phases of (Formula presented) and found that conduction and ferromagnetism were consistently suppressed by Fe doping.
Abstract: Author(s): Ahn, KH; Wu, XW; Liu, K; Chien, CL | Abstract: The effect of Fe doping (l20%) on the Mn site in the ferromagnetic ((Formula presented)) and the antiferromagnetic ((Formula presented)) phases of (Formula presented) has been studied. The same ionic radii of (Formula presented) and (Formula presented) cause no structure change in either series, yet conduction and ferromagnetism have been consistently suppressed by Fe doping. Colossal magnetoresistance has been shifted to lower temperatures, and in some cases enhanced by Fe doping. Doping with Fe bypasses the usually dominant lattice effects, but depopulates the hopping electrons and thus weakens the double exchange. © 1996 The American Physical Society.
273 citations
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TL;DR: In this paper, a two-layer heterogeneous model consisting of semiconducting grains separated by insulating grain boundaries was able to account for the observed temperature and frequency dependent electrical properties in CFGO ceramics.
217 citations
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TL;DR: In this paper, the authors reviewed the CoFe2O4 nanoparticles doped with various elements and their applications in various fields, including permanent magnets, magnetic recorders in high-density and micro-wave devices, and magnetic fluids.
140 citations