15-06-2015 At 04:00:00 PM
Speaker: Dr. Ashit k Pattanaik, Research Associate, Materials Science Division, BARC, Mumbai
Category: Experimental CMP Seminar
Venue: Lecture Hall
22-06-2015 At 04:00:00 PM
Speaker: Dr. Sanjoy Biswas , Korea Institute for Advanced Study)
Category: Seminar of General Interest
Venue: Lecture Hall
In this talk I will try to give an overview of the discovery of the Higgs-like resonance at the Large Hadron Collider, the role of the Higgs boson in the Standard Model, a special attention on it’s interaction with the top-quark: why it is important to measure the strength of this interaction and how we can do that.
24-06-2015 At 04:00:00 PM
Speaker: Dr. Sanjoy Biswas, (Korea Institute for Advanced Study)
Category: High Energy Physics Seminar
Venue: Lecture Hall
The Large Hadron Collider at CERN discovered a Higgs-like resonance.However, the confirmation of any resemblance with the Standard Model Higgs boson requires a precise measurements of it’s properties. In addition, it is also important to look for any hint of New Physics that might be associated with it’s production and decay. In this talk I will shed some light on these issues.
30-06-2015 At 04:00:00 PM
Speaker: Dr.Jyotirmoy Bhattacharya, (Durham University)
Category: HEP Seminar
Venue: Library Lecture Hall
In this talk, we shall introduce a quasi-local measure of quantumentanglement. It will be defined in terms of infinitesimal variations ofthe generating points, of the domain of dependence, associated with thesubsystem, whose entanglement, we monitor. Restricting our attention to 1+1and 2+1 dimensions, we will find that the condition of strong subadditivityrequires this quantity to be positive semi-definite. Moving on to theholographic context, we will relate this inequality with the null energycondition in the bulk (at the linearized level).
01-07-2015 At 04:00:00 PM
Speaker: Dr.Jyotirmoy Bhattacharya , (Durham University)
Category: Seminar of General Interest
Venue: Lecture Hall
In this talk, we will discuss some of the intricate geometricconnections of a wide class of phenomenon in strongly coupled quantum fieldtheories, through the gauge-gravity duality. We shall particularly considerexamples in the context of hydrodynamics, interesting scaling regimes (suchas hyperscaling violating regimes) and quantum entanglement.
02-07-2015 At 04:00:00 PM
Speaker: Dr. Shankhadeep Chakrabortty , IISER, PUNE
Category: HEP Seminar
Venue: Lecture Hall
06-07-2015 At 04:00:00 PM
Speaker: Dr. Nigel D. Browning ,PNNL, USA
Category: Spceial Colloquium
Venue: Lecture Hall
The last few years have seen a paradigm change in (scanning) transmissionelectron microscopy ((S)TEM) with unprecedented improvements in spatial,spectroscopic and temporal resolution being realized by aberrationcorrectors, monochromators and pulsed photoemission sources. Spatialresolution now extends to the sub-angstrom level, spectroscopic resolutioninto the sub-100meV regime and temporal resolution for single shot imagingis now on the nanosecond timescale (stroboscopic imaging extends this evenfurther to femtoseconds). The challenge now in performing experiments inan (S)TEM is to implement the in-situ capabilities that will allow bothengineering and biological systems to be studied under realisticenvironmental conditions. Performing experiments using in-situ stages orfull environmental microscopes presents numerous challenges to thetraditional means of analyzing samples in an electron microscope – we arenow dealing with the variability of dynamic process rather than a morestraightforward static structure. In this presentation, I will discussthe recent developments in the design and implementation of in-situ stagesbeing pursued at the Pacific Northwest National laboratory (PNNL). Examples of the use of these capabilities for the direct imaging ofinterfaces and defects, to identify the fundamental processes involved innucleation and growth of nanostructures from solution, and to investigatethe electrochemical processes taking place in next generation batterysystems will be presented. As the in-situ stages have been designed to beincorporated into both high spatial resolution aberration corrected (S)TEMas well as into high temporal resolution Dynamic TEM (DTEM), the potentialfor future experiments to study fast dynamics, including those in livebiological structures, will also be discussed.***This work was supported in part by the Joint Center for Energy StorageResearch (JCESR), an Energy Innovation Hub funded by the Department ofEnergy, Office of Science, Basic Energy Sciences. The development of theoperando stages was supported by the Chemical Imaging Initiative, aLaboratory Directed Research and Development Program at Pacific NorthwestNational Laboratory (PNNL). PNNL is a multi-program national laboratoryoperated by Battelle for the U.S. Department of Energy (DOE) underContract DE-AC05-76RL01830. A portion of the research was performed usingthe Environmental Molecular Sciences Laboratory (EMSL), a nationalscientific user facility sponsored by the Department of Energy’s Office ofBiological and Environmental Research and located at PNNL.
10-07-2015 At 04:00:00 PM
Speaker: Prof. Prabhat K. Giri ,Dept. Of Physics, IIT Guwahati
Category: General Seminar
Venue: Lecture Hall
The recent discovery and successful synthesis of large-areagraphene, with its unique physical properties, have led to thegrowing interest in its applications in diverse range of areas,including energy research. Chemically interfacing the inert basalplane of graphene with other materials has limited thedevelopment of graphene-based catalysts, composite materials anddevices. Physical functionalization of grapheme with noble metalswithout involving any chemical process to preserve its highstructural quality has remained challenging. In this talk, wewill present our recent results on the growth of single layergraphene by chemical vapor deposition followed by enhancedphysical functionalization of graphene with noble metalnanoparticles grown by radio frequency sputter deposition. Wewill show that site selective physical functionalization isactually mediated by in-plane defects in graphene [1]. Such agraphene-noble metal hybrid is used as a platform the controlledfabrication of ZnO nanowires on a graphene at a low temperature[2] and these graphene-ZnO nanowire exhibit superiorphotoconductive response as compared to the bare ZnO nanowires[3]. Next, we will discuss on the physical functionalization ofgraphene oxide (GO) prepared by a modified Hummer’s method anddiscuss the application of functionalized GO in the visible lightphotocatalysis. The performance of functionalized grapheme and GOwas compared for photocatalytic degradation of Methylene blueetc. Mechanism of enhanced photocatalytic performance offunctionalized GO is explored and implications of these resultswill be discussed.References:1. Ravi K. Biroju and P. K. Giri, J. Phys. Chem. C 118, 13833 (2014).2.Ravi K. Biroju, P. K. Giri, Soumen Dhara, Kenji Imakita, Minoru,Fujii, ACS Appl. Mater. Interf. 6, 377 (2014).3.Ravi K. Biroju, Nikhil Tilak, Gone Rajender, S. Dhara, P. K.Giri,Nanotechnology 26, 145601 (2015).
14-07-2015 At 04:00:00 PM
Speaker: Dr. Suratna Das ,(IIT Kanpur)
Category: General Seminar
Venue: Lecture Hall
Cosmic inflation has become an integrated part of moderncosmology as it elegantly explains why the universe is as we observe ittoday. In this talk, we will first unfold the success saga of inflationaryparadigm, eventually pointing out how more information about the earlydynamics of our universe can be extracted by just looking at the simplestpicture of inflation. We then would discuss couple of conceptual caveats ofinflationary paradigm and would seek for their plausible solutions.
14-07-2015 At 04:00:00 PM
Speaker: Dr. Suratna Das , (IIT Kanpur)
Category: General Seminar
Venue: Lecture Hall
Cosmic inflation has become an integrated part of moderncosmology as it elegantly explains why the universe is as we observe ittoday. In this talk, we will first unfold the success saga of inflationaryparadigm, eventually pointing out how more information about the earlydynamics of our universe can be extracted by just looking at the simplestpicture of inflation. We then would discuss couple of conceptual caveats ofinflationary paradigm and would seek for their plausible solutions.
16-07-2015 At 04:00:00 PM
Speaker: Dr. Suratna Das ,(IIT Kanpur)
Category: HEP Seminar
Venue: Lecture Hall
Cosmic inflationary paradigm beautifully explains the origin ofthe large structures, like galaxies and cluster of galaxies, we observetoday in our universe. But the fluctuations during inflation, which seedthese large scale structures, were quantum by origin, whereas thestructures which were developed due to gravitational instability seeded bythese quantum perturbations are all classical. Thus the persisting questionof how and when these primordial quantum perturbations become classicalstill plagues the basic concept behind inflationary paradigm. In this talkwe will seek for a plausible answer to this lingering issue by implementingcollapse models of quantum mechanics in early universe.
22-07-2015 At 04:00:00 PM
Speaker: Dr. R. K. Bommali , Department of Physics, IIT Delhi
Category: Experimental Condensed Matter Seminar
Venue: Library Lecture Hall
Silicon nitride thin films have been of interest since the advent of themicroelectronics revolution. It has been traditionally used for diverseapplications like dielectric gate material, impurity barriers, surfacepassivation, device encapsulation and optical coatings. These diverseapplications rest on the tunability of the composition and microstructureof this material. The discovery of the Quantum Confinement Effect inporous Si has led to interest in nano dimensional Si for applications inLEDs, non-volatile memories and photovoltaics. Si enriched silicon nitrideis a potential material for the realization of Si nanostructures embeddedin a ³transparent² silicon nitride matrix towards applications in variousoptoelectronic applications.In the present work we have carried out a detailed compositional study onsub-stoichiometric Silicon nitride films deposited by PECVD. The tuning ofthe optical and photocurrent properties with composition is presented. Theresults are understood by accounting for the role of the nanoscale a-Siinclusions in the substoichiometric silicon nitride films. Further a studyon the modification of the microstructure and the resultant change inphotoluminescence upon irradiation with swift heavy ions is also presented.
24-07-2015 At 04:00:00 PM
Speaker: Dr. Satya N. Tripathy , Institute of Physics, University of Silesia, Poland
Category: Experimental Condensed Matter Physics Seminar
Venue: Library Lecture Hall
The time evolution of cooperatively relaxing systems is a robust area ofresearch for decades. These systems include all kinds of glass formingsupercooled liquids and molten ionic conductors which offer potentialapplications in the field of material chemistry. The phenomenon of glasstransition involves slowing down of cooperative relaxing units from theorder of pico seconds (‰ 10-12 s) in the supercooled liquid state to themacroscopic times (‰ 100 s) in the glassy state. The measurement ofdifferent dynamic observables such as viscosity, dielectric relaxationtime and conductivity as a function of thermodynamic intensive parametersprovide the quantitative description of cooperative relaxation. In thiscontext, the dielectric relaxation spectroscopy is the appropriateexperimental tool to probe and understand the molecular dynamics of theglass forming systems in a large time window.In my talk, I will present the molecular dynamics of ionic deep eutecticsolvent (acetamide+ lithium nitrate/ sodiumthiocynate), sugar (D-fructose)and nano ceramic (Bi0.9Gd0.1Fe0.9Mn0.1O3) using broadband dielectricspectroscopy. I shall also discuss the potential connection betweenconductivity relaxation and the nature of secondary relaxation appearingbelow glass transition temperature. I will conclude my talk by discussingthe importance of mutarotation, conductivity scaling and space chargepolarization in glass forming systems.
24-07-2015 At 11:30:00 AM
Speaker: Prof.Federico Antinori, (INFN, Padova, Italy & CERN, Geneva, Switzerland)
Category: Colloquium
Venue: Lecture Hall
The LHC (Large Hadron Collider) at CERN (the European Organisation for Nuclear Research) is providing collisions of Pb nuclei at unprecedented energies. Such collisions allow to create a strongly interacting medium in which the colour decrees of freedom are active, and to study its properties in the laboratory. The key results from the study of Pb-Pb and p-Pb collisions during LHC Run 1 will be reviewed.
31-07-2015 At 04:00:00 PM
Speaker: Dr. Somnath Choudhury , IISER, Bhopal
Category: General Seminar
Venue: Lecture Hall
The measurements of the 125 GeV discovered Higgs boson andsearches for additional Higgs bosons in scenarios beyond the standardmodel will be summarized from the CMS experiment at the LHC, with a focuson Higgs boson decays to tau leptons. The CMS experiment is preparingitself to the upgrade of its different sub-detectors to cope with therising luminosity at the LHC, and an overview of the CMS detector upgradeprogramme will be presented with a focus on the new silicon pixel detectorto be installed in the year 2018.
04-08-2015 At 04:00:00 PM
Speaker: Dr. Tanumoy Pramanik ,Telecom ParisTech, France
Category: Quantum Information Seminar
Venue: Lecture Hall
Quantum steering is a kind of quantum correlation which can not be explained by local hidden state model (LHS). Absence of LSH model of a quantum system, say B, indicates that the uncertainty relation for the system B will be violated with the help of its steerable part. But, these feature does not captured properly using coarse-grained uncertainty relations,e.g., Heisenberg uncertainty relation, entropic uncertainty relation. We have formulated fine-grained steering inequalityfor both discrete variable and continuous variable systemsand overcome the limitation in coarse-grained steering inequalities. Monogamous nature of our steering inequality gives lower bound of secret key rate in one sided device independent way under individual attack. We also justify our work experimentally.
11-08-2015 At 04:00:00 PM
Speaker: Dr. Dipak Paramanik ,Iowa State University, USA
Category: General Seminar
Venue: Lecture Hall
Semiconductor based photodetectors often employ p-i-n junctiondiodes for detection of photons. Traditional thin film type ofstructures are made of layers of p type, i type and n typematerials. In this type of geometry the photon has to travelthrough the entire top layer without being absorbed before itreaches the depletion region. This reduces the efficiency of theconversion process. If we can realize an idealized geometry of thep-i-n junction where the photons are directly incident on thedepletion region then one can achieve higher quantum efficiencies.Such geometry will also allow us to locally probe in real-time thecharge carrier generation, transport and their interactions withdefects in the depletion region. In this talk, I will describeclean room fabrication of vertically aligned GaN core-shell nanopillar structure over a large area for high sensitive photodetector applications. I will also describe fabrication andcharacterization of different types of solar cells includingamorphous, heterojunction with intrinsic thin-layer (HIT) and tandem inorganic-organic solar cells.
13-08-2015 At 04:00:00 PM
Speaker: Dr. Rajesh Kumar Gupta ,ICTP, Italy
Category: General Seminar
Venue: Lecture Hall
In this talk I will present my recent work on the localization in thecase of supersymmetric extremal black hole. The technique ofsupersymmetric localization has been used quite successfully in the casesof supersymmetric field theory on compact spaces to compute observableslike partition function, expectation value of loop operators etc. I willdiscuss the computation of expectation value of Wilson loop operator onthe non compact space, AdS_2 times S^2, which is relevant for thecomputation of black hole entropy.
21-08-2015 At 04:00:00 PM
Speaker: Rajeev Kumar Jain, CP3-Origins, Denmark
Category: General Seminar
Venue: Main Lecture Hall
Lecture slides are available here: http://www.iopb.res.in/seminar/docs/Talk-IOPB-RKJain-Aug21.pdf
24-08-2015 At 04:00:00 PM
Speaker: Manimala Mitra, IISER, Mohali
Category: General Seminar
Venue: Lecture Hall
Proof of neutrino masses and mixings from a series ofoutstanding experimental efforts have opened a window to physicsbeyond the standard model of particle physics. There are well-definedunderlying theories which explain the electron volt neutrino masses.It is well known that Seesaw mechanism has its success in explainingthe smallness of neutrino mass. In this talk, I will give an overviewof neutrino mass generation through Seesaw, its different variationsand the interesting low energy, collider and astroparticle signatureof Seesaw.
25-08-2015 At 04:00:00 PM
Speaker: Manimala Mitra, IISER, Mohali
Category: HEP Seminar
Venue: Lecture Hall
A series of outstanding experiments have established thefact that standard model neutrinos have masses and very particularmixings. One of the attractive mechanism to explain the tiny massesof the neutrinos is Seesaw. In this talk, I will discuss about theorigin of neutrino masses in beyond standard model theories and thetestability of these theories in experimental searches, in particularneutrinoless double beta decay and collider search. One of the mostinteresting search process is lepton number violating search atnon-collider and collider experiments, that can probe the Majorananature of the light or heavy neutrinos. I will discuss differentcontributions in neutrinoless double beta decay that can arise frombeyond standard model theories, such as, sterile neutrino, Left-Rightsymmetric model and others and discuss the correlation of neutrinolessdouble beta decay with collider searches. In addition, I will alsodiscuss the possibility to probe Seesaw through Higgs window.
28-08-2015 At 04:00:00 PM
Speaker: C. Jebarathinam, IISER, Mohali
Category: Quantum Information Seminar
Venue: Lecture Hall
In this talk, we will discuss two measures for nonclassicalitywhich is nonzero also for correlations admitting local hidden variablemodel. Since these measures are analogous to quantum discord, I would liketo call them Bell and Mermin discord which go beyond Bell nonlocality andEPR-steering. We will discuss the origin of nonclassicality by using theframework of generalized nonsignaling theory. Interestingly, I find thatany quantum correlated state which has nonzero left and right quantumdiscord can give rise to nonzero Bell/Mermin discord for suitableincompatible measurements.
08-09-2015 At 04:00:00 PM
Speaker: Dr. R. Suriakarthick, Crystal Research Laboratory, Department of Physics, Anna University, Chennai
Category: General Seminar
Venue: Lecture Hall
The scarcity of electrical energy and the conventional energy sourcesprevails all over the world, which is estimated to be a big crisis infuture. Renewable energy sources can help to solve this problem, inparticular solar energy is considered as an ultimate way to produceeco-friendly power from a virtually inexhaustible source without noise orpollution. Solar cells operate on the principle of photovoltaic effect thatthe electron will flow between ‘p’ and ‘n’ type semiconductorsexposed to light (photons). The conversion efficiency increase and thecost of the solar cell decreases as the production done in large scaleusing abundant materials. To achieve this, it is necessary to develop newthin-film materials with good photovoltaic properties and appropriate bandgap for depositing them uniformly over large areas.The goal of present research work is to develop the solar cellsfree from the environmental contaminants using low-cost andnon-toxic materials. Promising thin film solar cell can be produced usingtransition metal chalcogenides as absorber. Hence, Silicon is the mostfrequently usedsemiconductor material for fabrication of solar cells. In our proposedwork, we will try to fabricate transition metal chalcogenides on Poroussilicon material and it’s a new type of Si-based heterostructure whichexhibit a periodical variation of porosity with depth. These structuresare easy to form and exhibit interesting optical properties. Hence, thesematerials are promising candidates for opto-electronic applications basedon Si technology.
09-09-2015 At 04:00:00 PM
Speaker: Kolahal Bhattacharya , DHEP,TIFR,Mumbai
Category: HEP Seminar
Venue: Lecture Hall
The potential of the neutrino mass hierarchy discovery by theICAL detector (under INO project) depends on how well the energy, angleetc. of the neutrinos can be measured. The methods involve patternrecognition and track fitting. Algorithms developed during the doctoralworks to perform these tasks will be presented. The sensitivity to thehierarchy, estimated from the reconstructed data, will be shown. I shallconclude with the future plan of works for attaining a better sensitivity.
14-09-2015 At 04:00:00 PM
Speaker: Prof. T. N. Narayanan, TIFR-Centre for Interdisciplinary Sciences Tata Institute of Fundamental Res
Category: General Seminar
Venue: Lecture Hall
Ultra-thin atomic layers open a possibility for interacting withindividual atoms in a material. At the same time, control over theirsynthesis, bulk production, large area single crystal synthesis,amenabilities in transfer processes etc. open avenues for engineering themfor suitable applications. Recently, development of new solids frominterfacing distinct atomic layers received tremendous scientificattention. A new solid from in-plane bond saturated and electronicallydissimilar atomic sheets, such as graphene and hexagonal boron nitride(hBN), called van der Waals solid is one such solid where new andunprecedented phenomena are found to be emanating from the interface. Thisis a paradigm shift in the materials science since these interface inducedphenomena are found to be tunable to large extends. Moreover, some ofthese tunable phenomena at the interfaces are useful in energy harvestingand storage applications. The solids generated by other means ofinterfacing atomic layers are also found to be excelling in variousfields. My talk will be focusing on some of the engineering aspects of 2Dmaterials for various fields.
15-09-2015 At 11:00:00 AM
Speaker: Chitta Ranjan Das , (JINR, Dubna)
Category: HEP Seminar
Venue: Lecture Hall
18-09-2015 At 04:00:00 PM
Speaker: Dr. Somnath De, PDF, IOP
Category: HEP Seminar
Venue: Lecture Hall
22-09-2015 At 04:00:00 PM
Speaker: Mainak Chakraborty, SINP, Kolkata
Category: General Seminar
Venue: Main Lecture Hall
30-09-2015 At 04:00:00 PM
Speaker: Prof. A.P. Balachandran, Physics Dept. Syracuse University, USA
Category: Colloquium
Venue: Lecture Hall
The talk emphasises that a fundamental approach to quantum physics uses states on a non-commutative algebra. The Hilbert space of quantum physics is then an emergent concept as shown by Gel'fand,Naimark and Segal (GNS). For commutative algebras, this approach leads to classical physics with the state as a probability measure.Thus quantum physics is just non-commutative probability theory. The talk applies the GNS construction to elementary systems like that of one q-bit. It explicitly shows how long-standing problems about entropy emergent from partial observations on identical particles can be easily solved.The analysis shows that repeated observations on quantum systems are stochastic maps and increase entropy : the argument does not involve temperature.Remarks on Gibbs state in the GNS approach are also made.
30-09-2015 At 02:45:00 PM
Speaker: Prof. T.R. Govindarajan, I.M.Sc., Chennai
Category: HEP Seminar of general interest
Venue: Main Lecture Hall
01-10-2015 At 04:00:00 PM
Speaker: Prof. T.R. Govindarajan, I.M.Sc., Chennai
Category: Colloquium
Venue: Main Lecture Hall
06-10-2015 At 11:30:00 AM
Speaker: Dr. Narayan Behera, IISc. Bangaore
Category: Seminar of General Interest
Venue: Main Lecture Hall
Identification of genes responsible for a cancer is a frontier area ofresearch. Microarray samples contain information about the gene expressionlevels of thousands of genes. Clustering similar genes and selecting thetop ranking genes help in identifying the key genes that play pivotalroles in specified biological conditions for diseased states. Today manyalgorithms exist for extracting these information but all have inherentlimitations. In this research a novel algorithm has been proposed for geneclustering, feature selection and classification of test microarraysamples with higher accuracy. The algorithm is a hybrid of clusteringalgortihm and evolutionary computation. The evolutionary computation usesan algorithm that utilizes the genetic principles of evolution to solve anoptimization problem. The genetic distance measure employed here is basedon entropy and mutual information which takes into account similarity ofthe gene expression levels as well as positive and negative correlationsbetween the genes. A study on the gastric cancer, colon cancer and braincancer microarray gene expression datasets and comparison with someexisting algorithms show the present algorithm to be superior. It is usedto find explicitly the top ranking genes that contain the most diagnosticinformation for gastric cancer. The present algorithm has potentialapplications in the computational drug discovery process.
07-10-2015 At 04:00:00 PM
Speaker: Dr. Utkarsh Mishra , HRI, Allahabad
Category: Quantum Information Seminar
Venue: Lecture Hall
We identify an effectively decoherence-free class of quantum states, eachof which consists of a minuscule and a large sector, against localnoise. In particular, the content of entanglement and other quantumcorrelations in the minuscule to large partition is independent of thenumber of particles in their large sectors, when all the particles sufferpassage through local amplitude and phase damping channels. The states ofthe large sectors are distinct in terms of markedly different amounts ofviolation of Bell inequality. In case the large sector is macroscopic,such states are akin to the Schrödinger cat.
08-10-2015 At 04:00:00 PM
Speaker: Dr. Muniyandi Muneeswaran, Department of Physics, National Institute of Technology Tiruchi
Category: General Seminar
Venue: Lecture Hall
In recent years, materials exhibiting both ferroelectricity and haveferromagnetism attracted much attention due to their significanttechnological promise in novel multifunctional devices. Very few materialsare naturally available and that too limited by coexistence of orders wellbelow room temperature and low cross-coupling coefficients. The term‘‘multiferroic’’ means coexistence of ferroelectric and magnetic orderingin one single phase or multiphase materials. However these two orderingparameters are mutually exclusive in principle because ferroelectricityrequires empty d shells, while magnetism requires partially filled dshells. Some of the important multiferroic perovskite oxides studiedincludes BiFeO3, BiMnO3 and ReMnO3 (Re = Y, Tb, Ho, Lu). However, theavailability of room-temperature single phase multiferroics is verylimited. Among the few room temperature single-phase multiferroicsreported so far, BiFeO3 (BFO) is an important multiferroics, which hasrhombohedrally distorted perovskite crystal structure with space group ofR3c at room temperature. It exhibits ferroelectric ordering below TC ~1083–1103 K and antiferromagnetic ordering below TN ~ 625–643 K. BFO. Themulti-functionality of BFO presents not only opportunities to studyfundamental physics but also helps to explore its potential applicationssuch as information storage, spintronics and sensors. In the presentstudy, a systematic effort is made to synthesis BFO nanoparticles byoptimizing the various parameters such as stoichiometry of the precursorsolution, pH value and annealing temperature. Besides, an attempt has beenmade to substitute a series of lanthanide ions (such as Dy3+, Pr3+ andTb3+) whose ionic radii are smaller than the Bi3+ ion and therebymodifying its physical properties. An enhancement of magnetization withincreasing Rare earth (RE) concentration in BFO nanoparticles has alsobeen observed. Further, leakage current characteristic of RE modified BFOis well improved compared to pure BFO due to the stable nature of RE.
08-12-2015 At 04:00:00 PM
Speaker: Prof. M.P.Das ,Australian National University, Australia
Category: Condensed Matter Theory Seminar
Venue: Lecture Hall
The Fermi surface is an abstract object in the reciprocal space for amaterial lattice, enclosing the set of all electronic band states thatare filled according to the Pauli principle. Its topology is dictatedby the underlying material crystalline structure. It is central topredictions of thermal, electrical, magnetic, optical andsuperconducting properties in metallic systems. A variety ofexperimental techniques are employed to study the topology of the Fermisurfaces. To name an important probe is the angle-resolvedphotoemission spectroscopy. On the other hand, in theory the densityfunctional approach is a first-principles method used to calculate theoccupied-band energies and the Fermi energy. In this talk I shallsurvey several key facts about Fermi surfaces in complex correlatedsystems, where a proper theoretical understanding is still lacking. Ishall address some critical issues onthe role of temperature andinteraction.
15-12-2015 At 04:00:00 PM
Speaker: Prof. M.P.Das, Australian National University, Australia
Category: Colloquium
Venue: Lecture Hall
Since, in particular physics, is a collective enterprise and is sobecause it is, itself, a fruit of the exquisitely social nature ofhuman living. So it s inevitable to encounter ethical issues in thenatural sciences, since the contest of differing interests and viewsof perennial in its practice, indeed essential to its momentum. Thecrucial ethical question always hangs in the air. How is the truthbest served ? In this talk we described some ethical aspects of ourown discipline of physics: their cultural context and the boundswhich they delineate for themselves, sometimes in transgression. WEargue that the minimalist ethic espoused in science, namely loyaltyto truth, is a bellwether for the much wider, more problematic, andmore vital consequences of ethics - and its failure - in humanrelationships at large.
18-12-2015 At 11:00:00 AM
Speaker: Sanjib Ghosh , SNU, Singapore
Category: CMP Seminar
Venue: Lecture Hall
29-12-2015 At 11:00:00 AM
Speaker: Mr. Sreeraj T.P, S N Bose National Center for Basic sciences
Category: TPSC HEP Seminar
Venue: Lecture Hall
31-12-2015 At 11:00:00 AM
Speaker: Dr. Himadri R. Soni, Lehrstuhl für TheoretischeChemie,Friedrich-Alexander U
Category: CMP Seminar
Venue: Lecture Hall
Using density-functional theory, we study the adsorption and reaction ofhydrogen and graphene. Fully hydrogenated graphene is known as graphane, astructure with altering carbon-hydrogen bonds directed up- and downwards.Electronically graphane is an insulator with a band gap of 3.5 eV.Graphane hydrogenated partially, on one side resulting in a coverage of0.5 ML is known as Graphone, a semiconductor with small band gap. In aprevious work, we studied the hydrogenation and dehydrogenation ofgraphene on Ni(111) by an interdisciplinary study combining DFT, XPS, andTPD. It was shown that hydrogen prefers fcc-hollow over top sides and, asa consequence, meta over ortho and para arrangements in the case of twoadsorbed hydrogen atoms. In the high coverage regime, coverages as high as1 ML (with respect to the nickel substrate) could be reached, withhydrogen arranged in a graphone structure. In summary, one obtainsstructures for hydrogenated graphene/Ni(111), which were shown to bethermodynamical not stable for freestanding graphene. This behavior wasexplained by a substrate effect of the Ni(111) surface. For a goldintercaleted system (graphene/Au/Ni(111)), however, lower maximal /coverages of ~ 0:25 ML were observed and a C4H (para) structure wassuggested. Therefore, the substrate seems to play a major role in metalsupported graphene. In order to investigate this in detail, herein, wepresent a systematic study of the reactivity of single-sided graphene,i.e., a graphene sheet which is accessible by an adsorbate from only oneside and which is occupied by a substrate from the other side. Therefore,we study the reactivity of hydrogen towards free-standing graphene, aswell as graphene/Ni(111) and graphene/Au/Ni(111) as representativesubstrates.