B. S. Nagaraja’s research while affiliated with NMAM Institute of Technology and other places

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Publications (20)


a Powder XRD patterns of pristine ZnO and Fe-doped ZnO samples; b extended view of a
a UV–vis spectrum (absorbance) and b Tauc’s plot of ZnO and Fe incorporated ZnO samples
FESEM images of ZnO and Fe-doped ZnO samples
EDX mapping of Zn, O, and different concentrations of Fe and EDX spectrum of Fe-doped ZnO
a Photo degradation curves. b First-order kinetics of Pristine and Fe doped ZnO nanoparticles

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An insight into noticeable dielectric response and effect of fe doping on photocatalytic efficiency (visible light) of ZnO nanoparticles synthesized through solution precipitation for harmful textile dye degradation
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October 2024

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64 Reads

Journal of Nanoparticle Research

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Jean Maria Fernandes

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Anupriya James

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[...]

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Iron (Fe)-incorporated zinc oxide (ZnO) nanoparticles (NPs) were synthesized via chemical precipitation technique and studied using powder X-ray diffraction (PXRD), field emission scanning electron microscopy (FESEM), and UV–vis diffuse reflectance spectroscopy. PXRD analysis reveals a hexagonal wurtzite structure for all the synthesized samples. UV–visible measurements demonstrate a reduction in the bandgap of ZnO with an increase in Fe concentration. The ZnO and Fe-incorporated ZnO NPs are studied for the degradation of organic textile dye under visible light irradiation. All the nanoparticles are thoroughly investigated using impedance and dielectric measurements in the frequency range of 20 Hz to 1 MHz. The results obtained are compared, interpreted, and presented in this paper.

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Effect of Cu Doping on Structural, Optical, and Electrical Properties of Sn2S3 Thin Films Prepared by Spray Pyrolysis

November 2023

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62 Reads

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2 Citations

JOM: the journal of the Minerals, Metals & Materials Society

The structural, optical, morphological, and electrical properties of polycrystalline copper-doped tin sulfide (Cu-Sn2S3) thin films with different concentrations of Cu dopants were synthesized using the spray pyrolysis method. Structural characterizations (powder XRD) revealed orthorhombic Sn2S3 crystal structure with Pmma space group. The XRD spectra showed improved crystalline quality and preferential orientation for the Cu-doped Sn2S3 thin films. Morphology of the prepared samples revealed sharp needle-shaped grains uniformly distributed throughout the sample. The UV spectroscopy results show 70–75% transmittance for 6 wt.% and 8 wt.% Cu-doped Sn2S3 thin films in the visible region. The bandgap values are decreased for the 4 wt.% sample and increased with an increase in the Cu concentration for 2 wt.%, 6 wt.%, and 8 wt.% with Sn2S3 thin films. The dielectric constant, dielectric loss, and electrical and optical properties were analyzed using UV data. Negative Hall coefficient values of prepared samples confirm the n-type semiconductor nature. Electrical conductivity increases with an increase in Cu concentration. These results indicate that the samples have potential applications in the optoelectronic field.


Visible-light-driven photocatalytic degradation of organic dyes over cubic-phase and hexagonal-phase CdS: a comparative study

March 2023

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109 Reads

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3 Citations

Journal of Materials Science: Materials in Electronics

Organic effluents—the gift of industrial development is a critical menace to environs as well as raising a question mark toward the sustainability of humans. In such a scenario, achieving consistent sunlight-driven photocatalytic degradation gains widespread attention due to its eco-friendly low-cost approach with high efficiency. Herein, the CdS-cubic nanoparticles have been synthesized using a simple chemical precipitation technique and structural transition to CdS hexagonal is obtained through annealing. Morphology study has validated the reduction in particle size of CdS cubic and corresponding enhancement in the surface are put forth by BET analysis. The better degradation capability of CdS cubic is demonstrated through the visible-light-driven photocatalysis of MB dye with a degradation rate constant of k = 0.02/min. Meanwhile, CdS hexagonal possesses a rate constant k = 0.005/min. The scavenger study reveals the vital role of conduction band electron and superoxide radical in decolorization. Moreover, lesser carrier recombination with more charge transfer is observed from PL and EIS, respectively, emphasizing the CdS-cubic nanoparticle's catalytic activity.


Systematic investigation and comparison of oxalic acid dihydrate, ammonium oxalate hydrate and ammonium hydrogen oxalate oxalic acid dihydrate single crystals

February 2023

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121 Reads

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5 Citations

Materials Science and Engineering B

Semiorganic crystals are hybrid materials that have captured the interest of researchers due to their improved material characteristics and applications. In the current work, single crystals of oxalic acid dihydrate (OAD), Ammonium oxalate hydrate (AHO), and Ammonium hydrogen oxalate oxalic acid dihydrate (AHOOD) were grown using a slow evaporation method. Single crystal and powder XRD measurements were carried out to elucidate their unit cell parameters, crystal system, and structural information. To comprehend the interplay of light and matter, optical investigations like UV–Vis Spectroscopy and photoluminescence studies were performed. Interaction of ammonium with oxalic acid, and thus formed crystals, was investigated using impedance spectroscopy. Detailed dielectric parameters such as dielectric constant, dielectric loss, impedance, conductivity, and electric modulus were explored as a function of frequency. Vickers hardness test was used to calculate the hardness, Meyer's number, brittleness, and fracture toughness. The crystals were determined to be of the hard materials group.


Low-pressure air plasma induced modification of structural and electrical properties of Gd 1− x Sr x MnO 3 manganites

December 2021

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46 Reads

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3 Citations

Radiation Effects and Defects in Solids

The structural and electrical properties of Gd1−xSrxMnO3 manganites pellets with different doping concentrations x (= 0.2,0.3,0.4,0.5) are modified using an easy low-pressure plasma irradiation method. Powder x-ray diffraction studies of the samples revealed that lattice parameters a and c increase with doping as well as plasma exposure except for x = 0.5 for which a decreases. On the contrary, lattice parameter b decreases with doping as well as plasma exposure and is more pronounced. The crystallite size increases with increasing doping concentration both with or without plasma exposure. Plasma exposure tends to decrease the Mn–O–Mn bond angle as well as the Mn–O bond length. The temperature-dependent electrical resistivity of samples reveals that the pristine Gd1−xSrxMnO3 exhibits insulating behavior for all the doping concentrations. However, the resistivity is enhanced at low temperature for all samples after plasma exposure. The variation of electrical resistivity after plasma exposure may be attributed to the disorder near the grain boundaries and cell volume. The resistivity behavior is unaffected by plasma exposure for all samples. The small polaron hoping model explains the conduction mechanism at high temperature while the conduction at low temperature is attributed to variable range polarons.


A systematic investigation on structural, electrical, linear and nonlinear optical properties of Zn:CdO thin films for optoelectronic applications

December 2021

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82 Reads

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12 Citations

Optical Materials

In the present work, a systematic study on structural, electrical, linear, and nonlinear optical properties of Zn doped CdO thin films prepared by Spray Pyrolysis (SP) technique is reported. X-ray diffraction (XRD) studies revealed the cubic, wurtzite structure, and polycrystalline nature of all the films. The observed results showed a decrease in lattice constant and unit cell volume with an increase in Zn doping concentration. Morphology study confirms uniform distribution of spherical grain-like structure with small voids. An increase in direct and indirect bandgap is observed with doping concentration up to 5 wt%, and the trend reverses at higher concentration. The significant effect of Zn doping on optical parameters such as absorption coefficient, extension coefficient, refractive index, optical dielectric constant, and optical conductivities are calculated for all thin films. Further, the optical studies were used to analyze the linear susceptibility, third-order nonlinear optical susceptibility, and nonlinear refractive index of the films. The observed values for χ(1),χ(3) and n2 are in the range from 0.03 to 0.09 esu, 3.51×10⁻¹⁶ to 1.02×10⁻¹⁴ esu, and 1.09×10⁻¹⁴ to 2.67×10⁻¹³ esu for pure and Zn doped thin films respectively. Hall coefficient and electrical studies indicate that the Zn doping influences the electrical properties. An n-type and ohmic behavior is also observed for these films. Optical and electrical results suggest that these Zn:CdO films can be a potential candidate for optoelectronic applications.


CuAg and AuAg bimetallic nanoparticles for catalytic and heat transfer applications

September 2021

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271 Reads

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20 Citations

Bimetallic nanoparticles (BNPs) have drawn significant attention due to their numerous applications. They demonstrate enhanced optical, electrical, thermal, and catalytic properties due to the synergistic effects of monometals present in them. In this work, CuAg and AuAg BNPs have been synthesized using a facile and economical chemical reduction method. Optical characterization was carried out using UV–visible spectroscopy, and effect of pH on optical absorbance was studied. For CuAg and AuAg BNPs, optimum pH was observed to be at 9.4 and 6.39, respectively. Morphological investigation confirms the average diameters of CuAg and AuAg BNPs were to be 65 nm and 30 nm, respectively. Photocatalytic property illustrates the reduction of 4-nitrophenol to 4-aminophenol with a 92% conversion percentage in the presence of CuAg BNPs in 4 min, and rate constant for the reaction was measured to be 8.98 × 10 –3 s ⁻¹ . But for the AuAg BNPs, the conversion percentage was 97% in 8 min and rate constant was found to be 7.95 × 10 –3 s ⁻¹ . Thermal conductivity and viscosity measurements of the nanofluids obtained with CuAg and AuAg BNPs have ascertained them to be efficient candidates for the heat transfer and catalytic applications. Graphic abstract


Investigation of cationic disorder effects on the transport and magnetic prop Pr 0.5 Sm 0.2 Sr 0.3 MnO 3 erties of perovskite Pr 0.7 - x RE x Sr 0.3 MnO 3 ( x = 0.0 , 0.2 ; RE = Nd, Sm, & Gd)

May 2020

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69 Reads

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33 Citations

Journal of Magnetism and Magnetic Materials

The strong influence of the A-site cationic size mismatch on the electrical, thermal and magnetotransport properties of Pr0.7-xRExSr0.3MnO3 (x=0.0,0.2 ; RE = Nd, Sm & Gd) pervoskite compound has been reported here. The considerable shifting of the insulator to metal transition temperature (TIM ) with the partial substitution of Pr3+ions by smaller radii rare-earth ions is discussed. The relevance of electron-electron scattering and the application of an adiabatic small polaron hopping (ASPH) model is explained to analyze electrical data. The temperature dependent volume fraction of the metallic ferromagnetic phase obtained from the percolation model of the electrical resistivity demonstrated a well resemblance with magnetic data. Analysis of Thermoelectric Power (TEP) data reveals that electron-magnon scattering is responsible for the thermoelectric transport in the metallic region whereas high temperature insulating region above Tpis well explained by the non-adiabatic SPH model.


Enhancement of temperature coefficient of resistance (TCR) and magnetoresistance (MR) of La0.67-xRExCa0.33MnO3 ( x = 0, 0.1; RE = Gd, Nd, Sm) system via rare-earth substitution

March 2020

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332 Reads

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33 Citations

We investigated the influence of 10% substitution of rare-earth (RE) elements on the crystallographic, transport, and magnetic properties of La 0.67– x RE x Ca 0.33 MnO 3 (RE = Nd, Sm, and Gd, x = 0.0, 0.1) manganite perovskite compounds. The bulk polycrystalline samples were synthesized using solid-state reaction method. The phase purity and crystal structure of studied samples were confirmed by room temperature X-ray diffraction followed by the Rietveld refinement analysis. A high temperature insulator to low temperature metal phase transition is observed in electrical transport measurement. We observed an enhancement in the temperature coefficient of resistance (TCR) and magnetoresistance (MR) by partially substituting La with RE ions. The maximum TCR ≈ 22% and MR ≈ 96% are observed in Gd doped sample. The magnetic transition temperature, T c , decreases from ∼254 K for the pristine sample to about ∼165 K for the Gd-doped sample. Our analysis of electrical and thermal transport data shows that the Small Polaron Hopping ( SPH ) is predominant at high temperatures conduction mechanism, whereas at low temperatures mechanism is dominated by electron-magnon scattering. The high temperature insulator paramagnetic phase to low temperature metallic ferromagnetic phase transitions are also observed in thermal conductivity and specific heat.


Bi2Te3-PLZT(9/65/35)-PVDF multifunctional nanocomposite films for futuristic energy harvestors

March 2019

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63 Reads

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1 Citation

AIP Conference Proceedings

This article highlights the influence of ternary material combination of thermoelectric 0.5Bi2Te3 (BT), ferroelectric 0.5(PLZT9/65/35) (PLZT) nanopowders dispersed in polymer PVDF matrix to form a 0.5Bi2Te3-0.5[Pb0.91La0.09(Zr0.65Ti0.35)0.9775O3]-PVDF nanocomposite thin film. BT and PLZT were prepared by using simple precipitation method to form 0.5BT-0.5PLZT-PVDF nanocomposite thin film. As heat treated BT and PLZT were characterized for phase analysis by powder X-ray diffraction, and microstructure studies by scanning electron microscopy and transmission electron microscopy. Nanocomposite thin films were characterized for room temperature dielectric, thermoelectric and ferroelectric studies. XRD patterns attested clear crystalline mixture of Bi2Te3 trigonal showing rhombohedral structure and perovskite PLZT showing ternary FERH, FETET, and FECUBIC structures at the morphotrophic phase boundary. SEM with EDS and TEM results of thermoelectric Bi2Te3, ferroelectric (PLZT:9/65/35) and 0.5Bi2Te3-0.5[Pb0.91La0.09(Zr0.65Ti0.35)0.9775O3] are reported. The nanoparticles of this system ranged between 17 nm and 82 nm. Dielectric, thermoelectric and ferroelectric results of the 0.5Bi2Te3-0.5[Pb0.91La0.09(Zr0.65Ti0.35)0.9775O3]-PVDF nanocomposite thin film was discussed. The remanent and spontaneous polarization and coercive field of BT-PLZT-PVDF film are observed as 2.52 µC/cm², 3.28 µC/cm and 196.63 kV/cm, respectively that could be interesting candidate for possible futuristic energy harvesting, biomedical and smart applications.


Citations (18)


... In addition to these peaks, the reflections obtained at 26 [44,46]. For the estimation of the [BaSnLa(S 2 CN(Et) 2 ) 2 ] semiconductor chalcogenide's average crystallite size, Debye Scherrer's relation shown by equation (6): Fig. 3(b) is illustrative of the FT-IR spectrum of the [BaSnLa(S 2 CN (Et) 2 ) 2 ] semiconductor palletized with KBr recorded in the range of 400-4000 cm − 1 . ...

Reference:

Sleuthing the performance of the sustainable mixed metal trichalogenide BaS:Sn2S3:LaS from single source route as an electrode material for charge storage
Effect of Cu Doping on Structural, Optical, and Electrical Properties of Sn2S3 Thin Films Prepared by Spray Pyrolysis
  • Citing Article
  • November 2023

JOM: the journal of the Minerals, Metals & Materials Society

... The coupling with Bi 2 S 3 is anticipated to facilitate charge transfer, thereby mitigating any potential adverse effects resulting from the differences in band positions between the two CdS polymorphs. Furthermore, the enhanced stability of hexagonal CdS, as indicated by the Rietveld refinement results, suggests its favorable role in forming heterojunctions, which can improve charge-separation efficiency and, consequently, the overall photocatalytic performance of the composite system [70,71]. ...

Visible-light-driven photocatalytic degradation of organic dyes over cubic-phase and hexagonal-phase CdS: a comparative study

Journal of Materials Science: Materials in Electronics

... In addition, they have superior optical properties to inorganic materials, particularly exceptional NLO properties with fast and large nonlinear responses across a wide frequency range. 5 However, the use of organic materials in the fabrication of industrial devices is hampered by their poor mechanical strength, low resistance to laser-induced damage, insufficient transparency, inability to grow to large sizes, and poor thermal strength. Inorganic materials, in contrast, have higher mechanical and thermal strength but have relatively poor NLO properties due to the lack of p electron delocalization. ...

Systematic investigation and comparison of oxalic acid dihydrate, ammonium oxalate hydrate and ammonium hydrogen oxalate oxalic acid dihydrate single crystals
  • Citing Article
  • February 2023

Materials Science and Engineering B

... thin film [29]. Further, few recent studies have reported modification of the structural and transport properties of doped manganites through plasma exposure [30][31][32]. However, additional research is needed to fully comprehend the influence of plasma irradiation on the characteristics of perovskites in macro or bulk forms. ...

Low-pressure air plasma induced modification of structural and electrical properties of Gd 1− x Sr x MnO 3 manganites
  • Citing Article
  • December 2021

Radiation Effects and Defects in Solids

... In the present work, we have investigated CdZnO thin films using the spray pyrolysis technique, focusing on modifying two critical parameters: the spray rate and the distance from the nozzle to the substrate. Our analysis revealed that the resultant thin films exhibited characteristics indicative of degenerate semiconductor behavior, contrary to the findings reported by Nagaraja et al. [17]. Furthermore, the band gap calculations revealed that deposited films showed a direct band gap, which differs from the observed changes in the indirect band gap reported in the mentioned literature. ...

A systematic investigation on structural, electrical, linear and nonlinear optical properties of Zn:CdO thin films for optoelectronic applications
  • Citing Article
  • December 2021

Optical Materials

... The absorption spectrum characteristics of plasmonic materials, such as plasmon resonance wavelength, can be tuned by nanoparticle properties like the shape and size of the nanoparticle. Therefore, The ability to finely control and tailor the properties of plasmonic materials at the nanoscale has expanded the utilization of plasmonic materials across a diverse range of applications, including mid-infrared (mid-IR) applications (Zhong et al. 2015), biomedical applications like cancer treatment (Liao et al. 2006;Lin et al. 2022), solar evaporation and clean water production (Chang et al. 2016), solar collectors (Mallah et al. 2022), catalysis (Dsouza et al. 2021), and energy saving in buildings (Elmi & Wang 2022). ...

CuAg and AuAg bimetallic nanoparticles for catalytic and heat transfer applications

... The perovskite, RMnO 3 , is essentially an antiferromagnetic insulator (R is a trivalent rare earth element). When R is replaced with a non-isovalent cation like Ba 2+ , Pb 2+ , Sr 2+ , Ca 2+ , or Te 4+ , Ce 4+ , a number of physical phenomena like the colossal magnetoresistance effect, metal to insulator transition, complex magnetic phase transitions such as Griffiths phase, charge order, etc. come into play [5,6]. The Jahn-Teller (J-T) effects and the double exchange (DE) coupling model are frequently used to explain these fascinating events. ...

Investigation of cationic disorder effects on the transport and magnetic prop Pr 0.5 Sm 0.2 Sr 0.3 MnO 3 erties of perovskite Pr 0.7 - x RE x Sr 0.3 MnO 3 ( x = 0.0 , 0.2 ; RE = Nd, Sm, & Gd)
  • Citing Article
  • May 2020

Journal of Magnetism and Magnetic Materials

... Despite several studies focusing on nickel-doped lanthanum ferrites, there is a lack of information about the effect of substitution of Ni 2+ in the magnetic and electric behavior of bulk LFO, which could extend the range of technological applications. Additionally, high-energy ball milling has been reported to enhance solid solubility in similar ferrites and, promotes high levels of strain, which could modify the magnetic structure of the LFO [36,37]. ...

Enhancement of temperature coefficient of resistance (TCR) and magnetoresistance (MR) of La0.67-xRExCa0.33MnO3 ( x = 0, 0.1; RE = Gd, Nd, Sm) system via rare-earth substitution

... Alternatively, materials are subjected to various types of radiation like ion beams [15][16][17], electron beams [18,19], neutron beams [20,21], gamma rays [22,23], and X-rays [24] to modify their physical properties. Ion and electron beam radiation have been used extensively to alter the properties of manganites which is largely attributed to the production of defects in the investigated systems [16,[25][26][27] These studies improve the likelihood of improvisation of the properties of manganites by exposing them to plasma, as plasma is an equilibrium mixture consisting of ions and electrons in addition to neutral atoms. This notion is supported by a study that has reported an increase in oxygen content in La0.7Ca0.3MnO3−δ ...

Investigation of the effect of electron beam irradiation on the structural and transport properties of half doped Nd0.5Sr0.5MnO3 manganites
  • Citing Article
  • February 2019

Physica B Condensed Matter

... The activation energy decreased with an increase in Sr content ( Table 3). The decrease in activation energy can be attributed to the increased probability of polaron hopping to the neighboring sites with the increase in Sr content [50,51]. These results confirm that resistivity in the PMI region gradually decreased with increase in Sr content. ...

Influence of sintering temperature on the electrical and thermal properties of bulk samples of Pr 2/3 Sr 1/3 MnO 3-δ
  • Citing Article
  • September 2018

Physica B Condensed Matter