Arnab Gangopadhyay

Characterization of Gd2O3 Nano Clusters

Gadolinium (Gd) is a weak magnetic element at room temperature. Gadolinium oxide (Gd2O3) is a poor semiconductor with para-magnetism. In this work Gadolinium oxide is prepared from the thermal dissociation of Gadolinium acetate. The average cluster size is found to be dependent on the number of the sintering time. In this present work an attempt has been made to characterize the developed Gadolinium oxide. Experimental probes used to characterize it are optical absorbance (UV-VIS); Fourier transformed infra red (FTIR) spectroscopy, DC current voltage characteristics (CVC) and photo-sensitivity studies of the developed specimens. Gadolinium oxide exhibits a good optical sensing property.

Experimental Investigation on Core Shell Nanocomposite of Cr1-xVxS2

Electrical and optical character of nanostructured Cr1-xVxS2 is studied here. This sulphide based nanoClusters (NC) was developed through chemical sol-gel route using (NH4)2Cr2O7 and NH4VO3 as active reagent and biopolymer gum acacia is used as capping agent. Core-shell NC has developed with sequential addition of active reagents in sulphation process. It is also possible to develop another type of core shell NC by reversal of the sequence of added reagents, i.e. interchanging the core and shell part. Experimental investigation including UV-VIS spectroscopy, dc current-voltage characteristics (CVC) have carried on. The results of CVC at room temperature (RT) show the distinctive features of localized energy levels. UV-VIS spectroscopic analysis shows absorption peak is blue shifted due to quantum confinement of nanoparticles. Overall appearance of optical absorption curve is completely different for two NCs. Peak positions are different for two types of core shell NC which confirms that the constituent materials of core and shell of two NC s has interchanged.

Estimation of particle size distribution of nanoparticles from electrical characteristics

An indirect method of estimation of size distribution of nanoparticles in a nanocomposite is proposed in this paper. The present approach exploits DC electrical current–voltage characteristics (CVC) of ZnO nanocomposite specimen in bio-polymer background. The nature of DC CVC is found to be oscillatory with respect to applied voltage. The nature of CVC is a consequence of Coulomb blockade (CB) phenomena of electrical conduction through a tiny nanoparticle. Considering the ZnO nanocomposites to be spherical, Coulomb-blockade model of quantum dot is applied here. The size distribution of particle is estimated from that model and compared with the results obtained from AFM and XRD analyses. The results from CVC are found to be consistent with these conventional microscopic results.

Transport properties of nanocomposite and its simulation with L-R-C circuit

The nano particles are represented in this communication by L-R-C equivalent circuit. The dc current voltage characteristics (CVC) of the proposed circuit have simulated using Circuit-Maker ® 2000. Experimental investigation on ZnO nano-composite with capping material gum acacia shows similar CVC. NPs are represented by C-R combinations to manifest the Coulomb blockade effect of a quantum dot. The capping material is represented by an inductor along with a resistance in series. Nine NPs with capping matrix are simulated. The dc current voltage characteristics (CVC) and gross feature of polarization nature obtained by experiment and simulation study are consistent.

Photonic aspect of sea shell

Sea shells are the bio-originating layered tough shelters of mollusks. Optical aspects and the functional nature of it are studied in this work using experimental probes like Fourier transform infra-red spectroscopy (FTIR) and UVVIS spectroscopy. It shows Photonic behavior in IR region of electromagnetic wave. Corresponding photonic band gap is estimated.

Material characteristics of sea shell

Sea shells are the bio-originated hard and tough shelters of the mollusks. Material aspects and the functional nature of the sea shell are studied in this work using different experimental probes like FTIR, UV-VIS. Electrical behaviour of the material is also studied here using ac and dc probes.

Left-handed Maxwellian aspects of natural pearl

Meta- material like behavior of natural Pearl are studied in this work. This work makes an attempt to analyze the Left Handed Maxwellian (LHM) properties of Pearl surface. The investigations carried out on natural Pearl specimen are optical reflectance and optical absorbance. Optical reflectance of Pearl surface with plane polarized monochromatic light in the form of verification of Fresnel equation shows distinct difference with that of conventional ordinary material. The UV-VIS analysis is also carried out for further analysis. The results obtained from the optical reflectance characteristics using polarized light indicate LHM behavior as expected for a LHM (type II or type II) meta-material. The overall analysis of the results shows the LHM character of Pearl surface.

LEFT-HANDED MAXWELLIAN BEHAVIOR OF NATURAL MICA

In this work, meta-material like behavior of natural Mica are studied. This work makes an attempt to analyze the left-handed Maxwellian (LHM) properties of Mica. The investigations carried out on natural Mica specimen are optical reflectance, optical absorbance and DC current–voltage-characteristics (CVC). Optical reflectance of Mica sheet with plane polarized monochromatic light shows distinct difference with conventional theoretical results. The DC CVC also measured with complete electromagnetic shielding. There exists a clear difference in DC characteristic for presence and absence of stray electromagnetic fields. The X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and ultraviolet-visible spectroscopy (UV-VIS) analysis are also carried out for further analysis. The results obtained from the optical reflectance characteristics using polarized light indicate LHM behavior as may be found in a meta-material. Micro-structural and electrical analysis shows that it is a nano-structured...