K. N. Rathod

Investigations of magnetoelectric behavior in BiFe0.95Co0.05O3 nanoparticles

Nanophasic BiFe0.95Co0.05O3 (BFCO) particles were synthesized using low cost, easy, simple, environment friendly and low temperature acetate precursor based modified sol–gel method. Influence of particle size and magnetic field on the structural, dielectric, impedance and a.c. conductivity of BFCO is investigated. X-ray diffraction (XRD) measurement has been performed to understand the structural modifications in the samples upon increasing the sintering temperature. Crystallite size (CS) increases from 33.62nm to 39.56nm due to agglomeration effect between the smaller crystallites. Effect of sintering temperature on the dielectric, impedance and conductivity has been studied and understood in the context of the creation of crystallite (particle) size and oxygen vacancies created due to high temperature sintering process. Magnetic field induced modifications in all these electrical properties [magnetoelectric (ME) effects] for the presently studied BFCO samples have been discussed on the basis of magnetos...

Studies on structural and electrical properties of pure and doped h-YMnO3

In the present communication, we report the results of the structural and electrical studies on pure YMnO3 (YMO) and Zr doped Y0.95Zr0.05MnO3 (YZMO) samples, synthesized using low cost sol-gel technique. To understand the structural properties, structural phases present and effect of doping on the structural behavior, X-ray diffraction (XRD) measurements were carried out for both the samples understudy. XRD results reveal the single phasic nature of both the samples having hexagonal unit cell structure. Improved crystal structure has been observed for pure YMnO3 sample while doping of Zr at Y-site degrades the structure of the sample. Improved dielectric constant and enhanced AC conductivity (σa) have been discussed on the basis of charge carrier polarization and correlated barrier hopping due to the localized state.

Preparation of CuO Quantum Dots by Cost-Effective Ultrasonication Technique

Due to exciting size-dependent chemical and physical properties, nanoscale materials have extensive range of applications compared with microstructural particles. CuO nanoparticles are very important among transition metal oxides because of their large number of applications. Quantum dots (QDs) of CuO (copper oxide) were prepared by the innovative ultrasonication method. Ultrasonic sound is used in this synthesis method to synthesize QDs of copper oxide. Structural and optical properties were studied in this research work. X-ray diffraction was used to study the formation of structural phase CuO QDs and found to be single phasic without any impurity. Transmission electron microscopic measurements were performed to study the morphology of QDs of CuO, which confirms spherical QDs with an average diameter of ∼4nm. In optical studies, absorption spectra of the CuO were analyzed by using UV–visible spectroscopy.

Studies on structural and electrical properties of nanostructured RMnO3 (R = Gd & Ho)

We report the results of the studies on the structural and electrical properties of multiferroic GdMnO3 and HoMnO3 materials synthesized by sol-gel route. Structural analysis of the results of X-ray diffraction (XRD) measurement shows that materials are found to be crystallized in orthorhombic and hexagonal symmetry, respectively for GdMnO3 and HoMnO3. Frequency dependent dielectric properties of nanostructured GdMnO3 and HoMnO3 were carried out using LCR meter in the frequency range of 100Hz to 2MHz at room temperature. Dielectric constant decreases with increasing frequency for both the nanostructured multiferroics which can be attributed to the dipole relaxation process. AC conductivity (σAC) has been measured for both the samples and fitted theoretically by using power law equation.

Effect of vanadium substitution on structural and electrical properties of sol–gel grown nanostructured zinc oxide

In the present communication, we report the results on the structural and electrical studies on nanostructured pure (ZnO) and Vanadium (V) doped Zn0.95V0.05O samples synthesized using low cost Sol-Gel technique. To understand the structural properties and their dependence on V substitution, X–Ray diffraction (XRD) measurement was carried out for both the samples understudy. XRD results reveal the single phasic wurtzite nature of both the samples showing hexagonal unit cell structure. A minor phase of ZnV2O6 is observed in V doped ZnO sample. Improved dielectric permittivity, enhanced ac conductivity (σac) and suppression in impedance have been discussed on the basis of structural modifications by the substitution of V in ZnO, enhanced charge carrier concentration, charge carrier polarization and correlated barrier hopping due to the localized state.

Investigations on structural, optical and electrical properties of V2O5 nanoparticles

In present communication, structural, optical and electrical properties of nanostructured vanadium pentoxide (V2O5) have been investigated. UV–Visible spectroscopy measurements were carried out in order to investigate the optical properties of as grown V2O5 samples. UV–Visible absorption spectrum shows a shifting in absorption peak towards lower wavelength from pure to different concentrated as grown samples. Value of optical band–gap (Eg), estimated from optical measurements, increases from 2.89 to 3.38eV with increase in concentration. Nanostructured V2O5 samples were synthesized using cost effective sol–gel method and final product was sintered at different temperatures. X–ray diffraction (XRD) measurement was performed to investigate the structural phases present which revealing the single phasic nature with orthorhombic structure. Crystallite size (CS), calculated using Scherer’s formula, is found to be ∼ 38.13 for 500°C sintered sample which increases to ∼ 51.31nm for higher temperature sintered sam...

Charge Trap Mechanism in Hybrid Nanostructured (YMnO3) Metal-Oxide-Semiconductor (MOS) Devices

Hybrid nanostructured Metal Oxide Semiconductor (MOS) capacitor was fabricated on silicon substrates (n-type) using chemical solution deposition with YMnO3 as an oxide layer. Electrical properties of MOS capacitor have been investigated with frequency dependence capacitance-voltage (C-V) characterization. The surface morphology of deposited layer was studied using the Atomic Force Microscopy (AFM). Hysteresis in the C-V loop and change in the values of Cminimum were described by a charge trap mechanism in the multiferroic oxide layer of MOS devices. While anomalous behavior in saturation capacitance in the inversion as well as in accumulation region and a shift in threshold voltage (VT) were explained in the vicinity of frequency depended Debye length (LDebye).

Structural properties and gas sensing behavior of sol-gel grown nanostructured zinc oxide

In this communication, we report the results of the studies on structural properties and gas sensing behavior of nanostructured ZnO grown using acetone precursor based modified sol-gel technique. Final product of ZnO was sintered at different temperatures to vary the crystallite size while their structural properties have been studied using X-ray diffraction (XRD) measurement performed at room temperature. XRD results suggest the single phasic nature of all the samples and crystallite size increases from 11.53 to 20.96nm with increase in sintering temperature. Gas sensing behavior has been studied for acetone gas which indicates that lower sintered samples are more capable to sense the acetone gas and related mechanism has been discussed in the light of crystallite size, crystal boundary density, defect mechanism and possible chemical reaction between gas traces and various oxygen species.

Studies on structural and electrical properties of nanostructured GdMnO3

In this communication, we report the results of the studies on structural and electrical properties of cost effective sol-gel grown nanostructured GdMnO3 manganites. Samples were sintered at different temperatures. Structural phases have been analyzed by performing the X-ray diffraction (XRD) measurements while crystallite size has been calculated using Scherer’s formula. AC conductivity (σAC) has been measured for all the samples and fitted theoretically by using power law equation. Variation in σAC has been understood on the basis of crystallite boundaries and oxygen ordering in all the samples. Nature of conduction in the samples has been discussed in the light of correlated barrier hopping mechanism.