Annual Report 2007-2008

Physical Sciences

The research projects and programmes supported under Physical Sciences covered a wide range of emerging topics. The technical evaluation was done by Programme Advisory Committees (PACs) on (a) Condensed Matter Physics and Materials Science, (b) Plasma Physics, High Energy Physics, Nuclear Physics, Astronomy & Astrophysics, Nonlinear Dynamics and (c) Lasers, Optics and Atomic and Molecular Physics. The PACs also monitored the progress made in ongoing projects on a regular basis.

Condensed Matter Physics and Materials Science

Among the projects that were sanctioned, a high sensitive magneto-optical imaging technique will be developed in one project. Polymeric gel electrolytes based solid state redox super-capacitors using composite conducting polymer electrodes will be studied in another project. Investigations on hybrid capacitor with nano materials for zero-emission vehicles will also be investigated in a different project. Amorphous carbon thin film having nanoparticle inclusions deposited by the modified vacuum plasma arc techniques will be studied in another project. In a different project, studies on tunable microwave materials and devices based on photonic band gap structure will be done. In a project, spin lifetime will be investigated in indirect semiconductors. Sensitized phosphate glass laser materials for applications in atmospheric communication systems will be developed. Photoinduced effects on Bi based chalcogenide multilayers thin film will be studied in a project. In a different project, investigations will be done on electrochemical synthesis of organised low dimensional group II-VI semiconductors. One project will be aimed towards development of cadmium sulphide- polyaniline heterojunction based room temperature LPG sensor. High pressure Raman studies of rare earth sesquioxides Ln203 (Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er,Yb Y) will be done in another project. Growth and studies of strongly correlated oxide systems, linear and non-linear optical properties of opto-electronic materials will be done in other project. Development and characterization of PVC- PEMA based solid polymer blend electrolytes for battery applications will be done in a different project. Investigation on the prospects of p-type ZnO films grown by RF magnetron sputtering will be done in a project. In a different project investigations will be made on metal induced crystallization of amorphous silicon for application in solar cells. Growth and characterization of dilute magnetic semiconductors will be investigated in another project. Other project will aim at OCVD growth and characterization of InGap/GaAs and InGaP quantum dot solar cells. Doped CuInO2 thin films for bipolar conductivity applications will be synthesized in a different project. A project will aim towards development of low cost sodium silicate based aerogels for thermal insulation applications. In a project, growth of 4-N, N-dimethylamino-4‘-N‘-Methyl-4-stilazolium to sylate (DAST) organic single crystals suitable for electro-optic sensors and to generate Tera Hertz waves will be investigated. Some insights on physicochemical properties of different electronic-ceramics using opto-impedance probe will be studied in other project. In a project, studies on optimization of time filtering methodology for stochastic processes and investigation of atomic diffusion in solids through Mossbauer Resonance will be done. Dehydration and rehydration behavior of microwave hydrothermally synthesized and naturally occurring zeolites will be studied in a project. Optimization of time filtering methodology for stochastic processes will be done and investigation of atomic diffusion in solids through Mossbauer Resonance will be made. A study on nano granular magnetic phase embedded in semiconductor for spintronics will be done in a different project. In another project, synthesis of high performance piezoelectric ceramic & crystals will be done for device fabrication.

Laser Induced Photoluminescence and Morphological studies of Nanophosphors will be studied in a different project. A project will aim towards development of lamp phosphors for solid state lighting. Dielectric spectroscopic and electro-optical studies of twisted grain boundary phases of liquid crystal will be studied in a project. Studies of the induction of smectic Ad and re-entrant nematic phases in binary mixtures of polar esters will be done in a different project.

Statistical theory of biological system and soft condensed matters will be studied theoretically in a different project. In another project, physics & modeling of silicon nanophotonic devices will be investigated. Electrochemical synthesis of organised low dimensional group II-VI semiconductors and the study of relaxation processes and scattering rates will be done in another project. Structural and Electronic properties of metal nanowires will be studied in a different project. Statistical Mechanics of force induced transitions in Bio-Polymers will be studied in another project. Electronic Transport in low dimensional systems will be investigated in another project. In another project Ab-initio study of electronic & optical properties of selected II-VI and III-V semiconductors & its alloys will be studied.

In the field of “Organic Electronics” few projects were also sanctioned. White organic light emitting diodes (WOLEDS) for general lighting applications is proposed to develop in a project. Molecular scale interface engineering with self-organized donor-bridge-acceptor structures: Electron transport in single molecular junctions will be studied in another project. Design and development of organic photovoltaic devices based on conjugated polymers is also proposed in another project. In a different project organic FETs and 3-terminal Structures for switching, memory and imaging applications will be studied.

In the field of low-temperature and high magnetic field, few more projects have been sanctioned. In a project, it was proposed to study electrical transport, magneto-transport, extraordinary (anomalous) hall resistivity and magnetic studies in nano-structured CMR manganites. A multipurpose uni-axial pressure device for resistivity, ac-susceptibility, thermopower and Hall effect measurements with variable low temperature (1.6K to 700 K), magnetic field (0 to 8 Tesla) and high pressure for the investigations of charge ordered half-doped manganites, bilayered manganites and spin ladder systems will be developed in a different project using a cryogen free magnet. In another project, the PI proposed to develop facilities on i) Torque magnetometer and ii) Scanning Hall probe Microscope/ Magnetometer. The Torque magnetometer facility would be useful in measuring magnetic anisotropy which was crucial in estimating hysteretic properties in a variety of magnetic materials. A physical property measurement system using the ever-cool technology will be developed in another project. Development of a closed-cycle liquid-helium cryostat (commonly called an “ever cool cryostat”) will be done in a different project. In another project, investigation of a class of magnetic materials which are interesting from both application as well as basic physics investigations will be undertaken. An investigation of coulomb interaction effects on mesoscopic and nanoscale transport with noise will be done in another project. Development of cryo-free superconducting magnet with room temperature bore will be made in a different project. In another project a vibrating sample magnetometer using a superconducting magnet will be developed.

Apart from the above one scientist have been awarded for Ramanna Fellowship.

Several interesting results were reported from ongoing projects.

Development of automated chemical spray pyrolysis unit along with the two stage process to deposit large area thin films based on important absorbing materials like Cu (In,Ga)Se2 and Cu (In, Ga) S2 took place in a project, which aims at fabrication of CuInS2/CuInSe & In2S3 based solar cells. Sprayed ß-In2S3 into an excellent window material and effective tailoring of its opto-electronic properties by controlling stoichiometry and doping was realized.

First ever Compton profiles of Rh (along [100] and [110] using 100Mci 241Am Compton spectrometer, developed in the project, was measured. Compton profiles of Hf, Dy, Gd, Er and Pr were also measured.

Comparison was made with theoretical Compton profiles within the HF and DFT (LDA and GGA) schemes of CRYSTAL-03 code. The data was also compared with the available APW and LCGO calculations.

Composition for UV light sensitive glass –C60 composites have been formulated in a project aimed for the development of photoactive glass-fullerene hetero-structures and studies on the viability of their use in designing photodiodes and photovoltaic cells. Two international patents were received by CGCRI group on Composition for preparing high concentration fullerene glass and a method for preparing the glass bulk monolith.

In another project, zero field-cooled (ZFC) and field cooled (FC) magnetization along with acmagnetization vs. Temperature and m-h loop measurements were reported for two series of ion-beam sputtered Fe-Cr GMR multilayers where the interface roughness is different. The magnetization of these multilayers relaxes as a function of time after being cooled in a small magnetic field of 100 Oe to a low temperature and then the magnetic field is switched off. An experimental evidence of the confinement of electrons in the Crspacer layers (quantum wells) was realized through extraordinary Hall Effect measurements.

Plasma, High Energy, Nuclear Physics, Astronomy & Astrophysics and Nonlinear Dynamics:

The projects sanctioned in this area are related to study of behavior of spatially extended dynamical systems on networks; Studies on fundamental properties of compact objects and their accretion disk using unified study of gravity, fluid dynamics and field theory; Theoretical investigations in light front field theory; investigations of BRST-symetries and supersymmetries; Study of effects of drift wave turbulences in dusty plasmas; Various experiments in large volume plasma produced by multiple compact ECR sources; Study of Plasma chamber setup for re-entry to atmosphere; An experimental study of quark gluon plasma in phenix experiment at RHIC (BNL, USA); and numerical and analytical investigation of strong-field processes driven by few-cycle laser pulses with gases and plasma waveguides; Study of the characteristics of top quark and search for new particles/phenomena at the DZERO experiment at Fermilab, USA; measurement of neutral current cross sections at high X and the structure function FI using polarized e beams at HERA II; Spectroscopic study of nuclei close to beta-stability line by using complete- and incomplete-fusion and deep-inelastic reactions; Feasibility study of neutrino less double beta decay in 124 sn; Studies on i) B meson decay and on ii) neutrino physics; investigating the di-lepton production rates in heavy ion collisions; and Studies on semi-classical techniques for many body nuclear systems and the role of symmetries.

Further, other projects sanctioned related to Study of effects of high spin states in non-relativistic and relativistic mean field formalism with good rotational symmetry; Investigations of incomplete fusion dynamics in heavy ion reactions at moderate and intermediate energies; Spectroscopic study of nuclei in the mass 80 region; Development of Multi purpose plasma ozone generator for various disinfectant applications; developing a simple model for the study of spectroscopy of charmed and beauty masons; calculating the meson spectra by imposing chiral symmetry theoretically; Theoretical studies on pentaquark baryons; Study of Polarization properties of radiation in a contact binary star perturbed by a third star; and Photometric and spectroscopic studies of variable stars and be stars.

One scientist working in this area has been awarded Ramanna Fellowship. Several interesting results were reported from ongoing projects.

In an ongoing project, the data on B mesons (branching fractions, CP asymmetries, mass and lifetime differences) obtained from several ongoing experiments were analyzed. Constraints on various new physics models were obtained. Supersymmetric effects on the production and decay of bottom quarks at the Tevatron as well as at upcoming LHC were analyzed. Several correlated channels were discussed.

In a different project, a comprehensive multi wavelength study of the star-forming region NGC 1893 was carried out to explore the effects of massive star formation. The PI could identify young stellar objects (YSOs) using near infrared colours, slitless spectroscopy and narrow-band photometry in the cluster region. Six research papers came out of the work done in the project.

Lasers, Optics, Atomic and Molecular Physics

The projects sanctioned during the year are:

• Design, fabrication and experimental characterization of photonic crystal fibers for applications in optical communications and sensors;
  
• Investigation of Bessel beams generated using optical fibers as large depth-of-field sub-micron scriber;
  
• Investigations on Laser plasma interaction and particle acceleration at ultra high power laser flux;
  
• Growing Large size KDP and ADP crystals by Sankaranarayanan Ramasamy method;
  
• Surface enhanced Raman scattering (SERS) studies of substituted methyl-0-nitrophenylsulfides;
  
• Linear and nonlinear optical properties of nano-size metal colloids in polymers;
  
• Development of Tunable laser based photo-acoustic sensors;
  
• To grow new organic crystals and their characterization as regards its structure and nonlinear opticalproperties;
  
• Laser spectroscopic study of atoms molecules and rare earth transitional metals in glasses/crystals;
  
• Studying the line shapes of rotational transitions in several molecules, specifically water and CO2 using diode laser spectrometer;
  
• Investigations of the physical processes of fundamental importance in understanding the dynamics of molecular collisions induced by electrons;
  
• Investigations of processes following L-and M-shell photo-ionization and analytical applications using EDXRF technique; and
  
• Study of the dynamics of the collisions of low energy of electron/positrons with atoms and molecules.

Two scientists working on the DST Projects in the area have been awarded Ramanna Fellowship. Several interesting results were reported from ongoing projects.

The field of quantum information processing and quantum computing using experimental NMR was developed. The nuclear spin had been treated as a cubit, which could be brought into superposition and itscoherence gave it the power of quantum computing. The achievements made in the project included,implementing one-dimensional and two dimensional quantum gates; ii. implementing CNOT, TOFFOLI and SWAP gates and a set of 2 and 3 qubit gates; iii. Preparing pseudo-pure states; iv. implementing Deutschjozsa and Grover’s search algorithms; v. studies of relaxation of pseudo-pure states; vi. Use of geometric phases in NMR QIP which were robust; vii. Implementing adiabatic algorithms; and viii. implementing
quantum games. In order to increase the number of qubits, the use of quadrupolar couplings (in nuclei with spin greater than ½) and dipolar couplings (in spin ½ nuclei) oriented in liquid crystal matrices were demonstrated. Creation of pair of pseudo-pure states, controlled-NOT and controlled-SWAP operations, entanglement and entanglement transfer has also been demonstrated. By this method upto 8-qubits in NMR has already been reached.

In another project, absolute frequency was measured in the D lines of Li, K, Rb, and Cs, using our ringcavity resonator. In addition, hyperfine structure in the D lines of all the alkali atoms (Li, Na, K, Rb, and Cs) was measured using a technique in which an acousto-optic modulator was directly locked to the hyperfine interval. The spectroscopy was done using home-built diode lasers and atomic vapor cells. The hyperfine structure measurements were the most precise to date. For laser cooling experiments in Rb and Yb. In Rb, a new vacuum chamber for loading a magneto-optic trap (MOT) from a Zeeman slowed atomic beam was designed and built to enable efficient evaporative cooling in a magnetic trap and hence to achieve Bose-Einstein condensation. In Yb also another vacuum system was designed to load the MOT from a Zeeman slowed atomic beam. In the latest design, the atoms are first slowed using 399-nm light, loaded into a MOT with the same 399-nm light, and then transferred to a MOT on the 556-nm inter-combination line.