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Dr. Amish G. Joshi

Dr. Amish G. Joshi
CSIR-Central Glass and Ceramic Research Institute-Naroda Centre; Ahmedabad - 382 330 · Naroda Centre

M.Sc. (Physics); Ph.D. (Physics) {Superconductivity}
Working on oxide ceramics and probing electronic structure through X-ray and UV Photoemission studies.

About

124
Publications
22,252
Reads
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2,170
Citations
Introduction
Current R & D activity focused on development of Glass base filters i.e. Indian Reference Materials/ Bharitya Nirdeshak Dravyas (BND®). In 11th FYP of CSIR network project “Fabrication of LED Devices and systems for solid-state lighting application”, established the state of the art major facilities at CSIR-NPL : (1) Molecular Beam Epitaxy to grow GaN based multi quantum well LED structure (2) Multi-technique surface analysis custom made system for probing various bulk & nanostructured material
Additional affiliations
September 2019 - present
Central Glass and Ceramics Research Institute
Position
  • Principal Investigator
April 2005 - April 2006
University of Kentucky
Position
  • BOYSCAST Fellow of DST, India
Description
  • Carried out work on Nb/Ni multilayer.
March 2002 - September 2019
CSIR-National Physical Laboratory, New Delhi - India
Position
  • Principal Investigator

Publications

Publications (124)
Article
Magnetization studies have been carried out on superconducting MgB2 (Tc=37 K) in the temperature range of 2–50 K and in magnetic fields up to 5 Tesla. From these measurements, values of the lower critical field Hc1(0), upper critical field Hc2(0) at 0 K are estimated to be ∼300 Oe and ∼12.5 Tesla, respectively, which yield a value of ∼26 for the Gi...
Article
Highly luminescent ZnO:Na nanocrystals of size ~2 nm were synthesized using a improved sol-lyophilization process. The surface analysis such as survey scan, core-level and valence band spectra of ZnO:Na nanocrystals were studied using x-ray photoelectron spectroscopy (XPS) to establish the presence of Na+ ions. The observed increase in band gap fro...
Article
X-ray circular magnetic dichroism (XMCD), X-ray photoemission spectroscopy (XPS) and ultraviolet photoemission spectroscopy (UPS) techniques were used to study the electronic structure of nanocrystalline (La0.6Pr0.4)0.65Ca0.35MnO3 near Fermi-level. XMCD results indicate that Mn3+ and Mn4+ spins are aligned parallel to each other at 20 K. Low M-H hy...
Article
The structural and magnetic properties of hole doped double perovskite La1.5Ca0.5CoFeO6 have been investigated by measuring X-ray photoemission spectroscopy (XPS), neutron powder diffraction and magnetization. A ferrimagnetic transition is observed at TC ~ 167 K. The presence of anti-site disorder (ASD) in La1.5Ca0.5CoFeO6 has also been demonstrate...
Article
Full-text available
Antiferromagnetic materials with a colossal exchange bias effect find applications as high-density spintronic devices. We report structural (geometrical and electronic) and magnetic studies in the polycrystalline Pr2CoFe0.5Mn0.5O6 double perovskite system. The observed lack of training effect suggests the existence of robust exchange bias. In addit...
Preprint
Full-text available
Double perovskite based magnets wherein frustration and competition between emergent degrees of freedom are at play can lead to novel electronic and magnetic phenomena. Herein, we report the structural and magnetic properties of an ordered double perovskite material Ho2CoMnO6. In the double perovskite with general class A2BB'O6, the octahedral B an...
Article
Dielectric anomaly observed in cubic Mn1.5Cr1.5O4 around ferrimagnetic ordering temperature (TN) suggests a possible magneto-dielectric coupling in the system. This report confirms the presence of a weak but significant magneto-dielectric coupling in the system. The ab initio calculations show a band gap of around 1.2 eV, with fermi-level closer to...
Article
Hydrophobic functionalization of cellulosic fabric (viscose) was carried out using helium/tetrafluoroethane (He/TFE) plasma, a commercially available fluorocarbon gas, at the atmospheric pressure. By selecting suitable plasma parameters, He/TFE plasma was produced and maintained in glow state so that the various fragments of TFE in plasma zone coul...
Article
The structural, electronic structure and magnetic properties of double pervoskite Tb2CoMnO6 have been investigated. Electronic structure analysis by X-ray Photoemission Spectroscopy Study (XPS) study reveals the presence of mixed oxidation state (Mn⁴⁺/Mn³⁺ and Co²⁺/Co³⁺) of B-site ions. Different interesting phenomena such as emergence of Griffith...
Article
Full-text available
Keywords: Magnesium oxide Thin films Dual ion beam sputtering X-ray photoelectron spectroscopy Conductive atomic force microscopy Ultrathin films of MgO (~6 nm) were deposited on Si(100) using dual ion beam sputtering in different partial pressures of oxygen. These thin films were characterized by X-ray photoelectron spectroscopy (XPS) for chemical...
Article
Some novel magnetic behaviours in double perovskite Eu2CoMnO6 (ECMO) have been reported. The x-ray photoemission spectroscopy study shows the presence of mixed valence states of transition metal ions. The UV-visible absorption spectroscopic study suggests that the ECMO has a direct wide band gap. A second-order magnetic phase transition as a sudden...
Article
Full-text available
Charge transfer across the interface of two materials in a composite can create reconstruction of bands near the interface which in turn brings multiple changes in physical properties of the materials. Thus, investigation of band structure experimentally is of immense importance in studying composite materials to understand their physical propertie...
Article
Crystal structure, electronic structure, dc and ac magnetization properties of the hole substituted (Sr2+) partially B-site disordered double perovskite Pr2-xSrxCoMnO6 system have been investigated. The XRD pattern analysis showed the systematic decrease in the lattice parameters owing to the enhanced oxidation states of the Co/Mn ions. The electro...
Preprint
Full-text available
The structural and magnetic properties of double perovskiteTb2CoMnO6 have been investigated. Electronic structure analysis by XPS study reveals the presence of mixed oxidation state (Mn4+/Mn3+ and Co2+/Co3+) of B-site ions. The dc and ac magnetization measurements reveal different interesting phases such as Griffith phase, re-entrant spin glass, me...
Article
Sn0.97−yCo0.03NiyO2 (0≤y≤0.04) nanocrystals, with the average crystallite size in the range from 7.3 nm (for y=0.00) to 5.6 nm (for y=0.04), have been synthesized using a pH-controlled chemical coprecipitation technique. All the nonstoichiometric and stoichiometric point defects arising in the nanocrystals on codoping have been identified, and thei...
Preprint
Magnetoelectric multiferroic composite of two types of multiferroic (Type I and II) consisting BiFeO3 and TbMnO3 is studied for enhanced magnetic and transport properties. A narrower band gap is estimated from the UV-visible absorption spectrum from that of BiFeO3 and TbMnO3. With known value of band gap, the band structure was estimated from the v...
Preprint
Sn$_{0.97-y}$Co$_{0.03}$Ni$_{y}$O$_{2}$ (0 $\leq y \leq$ 0.04) nanocrystals, with average crystallite size in the range of 7.3 nm ($y$=0.00) to 5.6 nm ($y$=0.04), have been synthesized using pH-controlled chemical co-precipitation technique. The non-stoichiometric Sn related defects and the O related stoichiometric Frenkel defects arising in the na...
Preprint
Full-text available
Electronic structure, electrical transport, dc and ac magnetization properties of the hole substituted (Sr2+) partially B-site disordered double perovskite Pr2-xSrxCoMnO6 system have been investigated. Electronic structure was probed by employing X-ray photoemission spectroscopy (XPS) measurements. The study suggested the presence of mixed valence...
Article
Electronic structure of Pr2CoFeO6 (at 300 K) was investigated by x-ray photoemission spectroscopy (XPS) and x-ray absorption spectroscopy techniques. All three cations, i.e. Pr, Co and Fe were found to be trivalent in nature. XPS valance band analysis suggested the system to be insulating in nature. The analysis suggested that Co3+ ions exist in lo...
Article
Diluted magnetic semiconductor Ti1−xMnxO2­ (0.0 ≤ x ≤ 0.06) nanoparticles have been synthesized by sol–gel technique. Phase purity, structural, micro‐structural, and vibrational properties of the samples have been studied by X‐ray diffraction, transmission electron microscopy (TEM), high‐resolution TEM, and Raman spectroscopy. UV–Vis and photolumin...
Preprint
Electronic structure near Fermi level of Pr2CoFeO6 (at 300 K) was investigated by X-ray photoemission spectroscopy (XPS) technique. All three cations, i.e., Pr, Co and Fe were found to be trivalent in nature. XPS analysis also suggested the system to be insulating in nature. Moreover, Raman spectroscopy study indicated the random distribution of th...
Article
Several methods such as hydrothermal, co-precipitation, solution combustion, and pulsed laser deposition have been reported for the synthesis of zinc oxysulfide (ZnOxS1-x). The photocatalytic activity of ZnOxS1-x for the inactivation of organic pollutants and bacteria are well-known. This paper is the first ever study on novel application of ZnOxS1...
Article
We report results of the studies relating to the development of the emerging nanostructured molybdenum trioxide (nMoO3)-based biocompatible label-free biosensing platform for breast cancer detection. The structural and morphological studies of the synthesized nMoO3 nanorods were investigated by XRD, SEM, X-ray photoelectron spectroscopic, and TEM t...
Article
X-ray photoemission spectroscopy (XPS), X-ray diffraction (XRD) and transmission electron microscopy (TEM) have been used to study the structural and morphological characteristics of cobalt doped tin(IV) oxide (Sn1−xCoxO2; 0 ≤ x ≤ 0.04) nanocrystals synthesized by a chemical co-precipitation technique. Electronic structure analysis using X-ray phot...
Article
Herein, multiwall carbon nanotubes (MWCNTs), reduced graphene oxide (rGO), graphene oxide-carbon nanotubes (GCNTs) hybrid reinforced acrylonitrile butadiene styrene (ABS) nanocomposites have been prepared by micro twin screw extruder with back flow channel and the effect of different type of fillers on the nanomechanical properties are studied. The...
Article
Recently, we reported the synthesis and investigations of EuSr2Bi2S4F4 and Eu2SrBi2S4F4. We have now been able to induce superconductivity in EuSr2Bi2S4F4 by Se substitution at the S site (isovalent substitution) with Tc = 2.9 K in EuSr2Bi2S2Se2F4. The other compound, Eu2SrBi2S4F4, shows a significant enhancement of Tc. In Se-substituted Eu2SrBi2S4...
Article
We synthesized double perovskite Pr2FeCrO6 by solid-state method. Analysis of its X-ray powder diffraction shows that the compound crystallizes in a centrosymmetric structure with space group Pbnm. Our X-ray photoelectron spectroscopy (XPS) studies show that all the cations are present in +3 oxidation state. Magnetization studies of Pr2FeCrO6 show...
Article
This work reports the change in the structural, dielectric and optical behaviour of Cr-doped LaInO3 nanoparticles synthesized via sol-gel method. X-ray diffraction patterns confirm that systems crystallize in orthorhombic Pnma space group. Raman spectroscopy measurements exhibit blue-shift in Raman modes with Cr-doping due to the compressive stress...
Article
Crystalline, uniform and stoichiometric thin films of CdS have been fabricated on soda lime glass (SLG) substrates using vacuum thermal deposition method in the presence of hydrogen sulphide (H2S) atmosphere. The consequence of ambient H2S on the growth, quality and structure-property relationship of vacuum deposited CdS thin films has been investi...
Article
In this investigation, we have synthesized Bi0.5La0.5Fe0.5Mn0.5-xTixO3 (where x = 0 and 0.05) samples. The Rietveld refinement of X-ray diffraction(XRD) patterns shows that the systems crystallize in the orthorhombic phase with the Pnma space group. The observed Raman modes support the XRD results. The appearance of prominent A1-3 and weak E-2 mode...
Article
In this investigation, we have synthesized Bi0.5La0.5Fe0. 5Mn0.5-xTixO3 (where x = 0 and 0.05) samples. The Rietveld refinement of X-ray diffraction (XRD) patterns shows that the systems crystallize in the orthorhombic phase with the Pnma space group. The observed Raman modes support the XRD results. The appearance of prominent A1-3 and weak E-2 mo...
Article
We have synthesized two new Eu-based compounds, EuSr 2 Bi 2 S 4 F 4 and Eu 2 SrBi 2 S 4 F 4 , which are derivatives of Eu 3 Bi 2 S 4 F 4 , an intrinsic superconductor with T c = 1.5 K. They belong to a tetragonal structure (SG: I4/mmm, Z = 2), similar to the parent compound Eu 3 Bi 2 S 4 F 4. Our structural and 151 Eu Mö ssbauer spectroscopy studie...
Article
Structural, magnetic and magneto-transport properties of nanocrystalline (La0.4Pr0.6)0.65Ca0.35MnO3 have been investigated along with their electronic structures. Temperature dependent magnetization measurement shows different magnetic phases in different temperature regions. (La0.4Pr0.6)0.65Ca0.35MnO3 completely transforms into a ferromagnet below...
Article
Full-text available
A geometrically frustrated magnetic CuMnO2 system has been investigated because of its rich magnetic properties. Neutron diffraction, synchrotron X-ray, magnetic, X-ray photoemission spectroscopy (XPS) and UV-Visible spectroscopy measurements have been carried out on CuMnO2 and 5% Fe doped CuMnO2 samples. Fe doping reduces the distortion. Moreover,...
Article
(La0.6Pr0.4)0.65Ca0.35MnO3 system has been synthesized via a sol-gel route at different sintering temperatures. Structural, transport and optical measurements have been carried out to investigate (La0.6Pr0.4)0.65Ca0.35MnO3 nanoparticles. Raman spectra show that Jahn-Teller distortion has been decreased due to the presence of Ca and Pr in A-site. Ma...
Article
Full-text available
The effect of chemical pressure on the structural, transport, magnetic and electronic properties of ZnV2O4 has been investigated by doping Mn and Co onto the Zn sites of ZnV2O4. With Mn doping the V–V distance increases and with Co doping it decreases. The resistivity and thermoelectric power data indicate that, as the V–V distance decreases, the s...
Article
Full-text available
The chemical pressure effect on the structural, transport, magnetic and electronic properties (by measuring X-ray photoemission spectroscopy) of ZnV2O4 has been investigated by doping Mn and Co on the Zinc site of ZnV2O4. With Mn doping the V-V distance increases and with Co doping it decreases. The resistivity and thermoelectric power data indicat...
Article
In this study, we report on investigations of the electronic structure of SrTiO3 annealed at temperature ranging between 550 and 840 °C in an ultrahigh vacuum. Annealing induced oxygen vacancies (Ovac) impart considerable changes in the electronic structure of SrTiO3. Using core-level photoemission spectroscopy, we have studied the chemical potenti...
Article
A photoactive electrode comprising of lead sulfide (PbS) and cadmium sulfide (CdS) quantum dots (QDs) and functionalized graphite platelets (FGP) was prepared by assembling them onto titanium dioxide (TiO2), which functioned as the wide band gap semiconducting scaffold. The QDs were cumulatively capable of harvesting portions of visible and infrare...
Data
Full-text available
A photoactive electrode comprising lead sulfide (PbS) and cadmium sulfide (CdS) quantum dots (QDs) and functionalized graphite platelets (FGPs) was prepared by assembling them onto titanium dioxide (TiO2), which functioned as the wide band gap semiconducting scaffold. The QDs were cumulatively capable of harvesting portions of visible and infrared...
Article
Wet chemical passivation of n-GaN surface using Ru based solution has been reported. X-ray photoelectron spectroscopy characterization of the GaN surface revealed removal of surface oxides by the introduction of Ru complex species. Ni/n-GaN Schottky barrier diodes were fabricated on passivated GaN and a remarkable improvement in Schottky barrier he...
Article
Composites of poly(3,4-ethylenedioxypyrrole) or PEDOP and poly(3,4-ethylenedioxythiophene) or PEDOT enwrapped Sb2S3 nanorods have been synthesized for the first time for use as supercapacitor electrodes. Hydrothermally synthesized Sb2S3 nanorods, several microns in length and 50-150 nm wide, offer high surface area and serve as a scaffold for coati...
Article
We report the effect of growth temperature on defect states of GaN epitaxial layers grown on 3.5 μm thick GaN epi-layer on sapphire (0001) substrates using plasma assisted molecular beam epitaxy. The GaN samples grown at three different substrate temperatures at 730, 740 and 750 ◦C were characterized using atomic force microscopy and photoluminesce...
Article
We report the effect of growth temperature on defect states of GaN epitaxial layers grown on 3.5 μm thick GaN epi-layer on sapphire (0001) substrates using plasma assisted molecular beam epitaxy. The GaN samples grown at three different substrate temperatures at 730, 740 and 750 °C were characterized using atomic force microscopy and photoluminesce...
Article
Fabrication of cost-effective, rapid and specific paper based point-of-care (POC) diagnostics based on the principles of bio-recognition is currently vanguard of biomedical research area as it is playing a key role in the early diagnosis and treatment resulting into the inhibition of infection and reducing the mortality rate. In the present report,...
Article
The spinel ferrite system CoZnzGezCrx-zFe2-x-zO4 with z= x2; x = 0.60, 0.65 and 0.70 was studied by Mà T (ZFC-FC) DC magnetization at low and high fields in the temperature range 5K to 300K, MàH measurements with high field up to 55 kOe at 15K temperature and low field AC susceptibility in temperature range 77K to 300K. We observe thermo-magnetic i...
Article
A new electrochromic viologen, 1,1′-bis-[4-(5,6-dimethyl-1H-benzimidazole-1-yl)-butyl]-4,4′-bipyridinium dibromide (IBV) was synthesized by di-quaternization of 4,4′-bipyridyl using 1-(4-bromobutyl)-5,6-dimethyl-1H-benzimidazole. X-ray photoelectron spectroscopy confirmed the formation of the IBV (viologen) salt as distinct signals due to quaternar...
Article
Reduced graphene oxide (RGO) due to its excellent electrochemical properties and large surface area, has recently aroused much interest for electrochemical biosensing application. Here, the chemically active RGO has been synthesized and deposited onto an indium tin oxide (ITO) coated glass substrate by the electrophoretic deposition technique. This...
Article
The advantage of hydrothermal synthesis of semiconductor quantum dots (QDs) over the control of particles size, morphology and stability is reported here. In a typical synthesis procedure, the zinc and sulfur precursor molar ratio of 1:3 was used in an aqueous solution at 150 °C. The cubic phase of ZnS with average particles size of 5 nm was confir...
Article
Atmospheric pressure glow plasma was created using He/1,3-butadiene (BD) mixture. Stable milky white glow He/BD plasma was confirmed by spike free smooth I–V waveform. Optical emission spectroscopy (OES) spectra of He/BD plasma showed fragmentation of BD inside the plasma zone into small species. OES analysis also showed that fragmentation of BD co...
Article
Ultrathin films of MgO (~ 6 nm) were deposited on Si(100) using dual ion beam sputtering in different partial pressures of oxygen. These thin films were characterized by X-ray photoelectron spectroscopy (XPS) for chemical state analysis and conducting atomic force microscopy for topography and local conductivity map. No trace of metal Mg was eviden...
Article
Nanostructured Zr-doped α-Fe2O3 thin films were successfully synthesized and studied for photoelectrochemical (PEC) generation of hydrogen through splitting of water. PEC data were analyzed with the supporting information obtained by Scanning electron microscopy, X-ray diffraction, Raman spectroscopy, UV-Vis optical spectroscopy, and X-ray photoele...
Article
In present work sintered samples of gadolinium doped magnesium ferrite has yielded a linear response of resistivity for wide range of humidity. From 10 % to 95%RH change, a. c. resistivity of 2 mol% Gd doped sample drops linearly from 3.39×107 to 3.2×105 Ω-cm at 1 kHz. Gd doping also enhanced porosity. XPS shows enhancement in lateral oxygen peaks...
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Graphene, a single layer of graphite, has recently attracted considerable attention owing to its remarkable electronic and structural properties, and its possible application in many emerging technologies including optoelectronics 1 . Since the development of straightforward chemical synthesis methods of graphene, scientists have been on the look o...
Article
The appearance of ferroelectricity has been observed in magnetically ordered Co(Fe1−xTix)2O4 at room temperature. Magnetization and dielectric constant is found to increase with Ti doping. It is observed from an X-ray Photoemission Spectroscopy study that Ti goes to the octahedral site with (+4) ionic state. An M–H hysteresis curve at room temperat...
Article
A simple, green mechanism for the UV assisted synthesis of graphene in the presence of phosphotungstic acid (PTA) is presented. The reduced graphene oxide (RGO) after UV exposure in the presence of PTA has been further identified as an efficient UV-absorber due to its complexation with PTA. This in turn could be used as an excellent template for th...
Article
CdSe/CdS core/shell nanocrystals have been synthesized through a low cost and simple two-phase thermal route. The optical spectroscopy and structural characterization evidenced the core/shell structure of the CdSe/CdS nanoparticles. The X-ray diffraction patterns of CdSe and CdSe/CdS nanoparticles exhibited peak positions corresponding to those of...