Annual Report 2004-2005

Scientific Research

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. The sub-area wise projects funded are given below:

Condensed Matter Physics and Materials Science

• A project to overhaul and upgrade an existing Raman spectroscopy system and carry out studies of (a) collective excitations in CMR manganites and charge-ordering systems; (b) orbiton excitations in orbitally-ordered manganites as a function of pressure and doping; (c) electronic Raman scattering in manganites; and, (d) temperature dependence of phonons and physical properties of newly synthesized carbon peapods – C60 and C70 inside nanotubes has been taken up.
• Developing a low-cost non-vacuum technique for fabricating efficient thin film Cu (InGa) Se2 solar cells. Facilities to measure resistivity and magnetoresistance from 77K to 300K would be created in another project.
• Investigations on the effect of photo-isomerization and photo-driven reorientation in liquid crystalline materials exhibiting various types of phases possessing orientational and/or positional ordering using a variety of probes.
• Novel core/shell and quantum dot-quantum well (QDQW) nanostructures would be synthesized and their electronic structure would be studied employing optical absorption spectroscopy and luminescence spectroscopy along with nonlinear optical spectroscopies.
• A multi-scale model for the fracture of glassy polymers would be constructed in which a molecular model would be integrated with a large-scale finite element model to simulate fracture at microscopic scale.

Studies on Metallic and Bimetallic clusters would be carried out.

• Apart from the above, projects were also sanctioned on topics such as ab-initio study of electronic and optical properties of selected II-VI and III-V semiconductors and its alloys : pressure effects; fabrication of solar cells with CuInSe2 films as absorber layer prepared by Rapid Thermal processing of stacked elemental layers; electronic structure of unconventional Colossal Magneto- Resistive Materials; Thin Film Solar Cells based on dye sensitized nano-porous TiO2 and polymers; photoelectrochemical detoxification of water using spray deposited oxide semiconductor thin films.

Some of the achievements in on-going programmes were as under:

• At UGC-DAE Consortium for Scientific Research, Indore, an Inverse Photoemission Spectrometer (IPS) had been built with completely indigenous design. As an important spinoff, a Knudsen Cell had also been designed and indigenously fabricated which would be useful for growing thin films and nanostructures on surfaces. It used a pyrolytic boron nitride crucible with resistive heating and water cooling. A temperature of 1000ºC had been achieved at a pressure of about 5 X 10-10 mbar.
• At I.I.Sc. Bangalore, an Ultra High Vacuum Low Temperature Scanning Tunneling Microscope (UHV-LTSTM) had been indigenously fabricated which worked in magnetic fields up to 6T. It was being optimized for its performance. In the course of this development, a piezoelectric tube walker and a noise measurement set-up had been built that could measure noise by ac in the presence of a dc bias. These experiments had been carried out up to 12T. It had also been found that thermal relaxation in charge ordered Pr0.63Ca0.37MnO3 in the presence of a magnetic field close to Tc indicated existence of low lying excitation.
• At I.I.T. Madras, facilities of the Low Temperature Laboratory had been upgraded and augmented. A new helium recovery compressor had been installed and test run had been carried out successfully (Figure 2.4). A VHF SQUID magnetometer had also been upgraded.
• At M.L. Sukhadia University, Udaipur, a 20 Ci based 137Cs Compton Spectrometer for the best possible momentum resolution and count rate had been successfully designed, fabricated and built. Isotropic Compton profiles of Al, Ta, By, Hg, Au, CdS, Sm and directional profiles of Ta had also been measured.
• At IACS, Kolkata, samples of AgI-Ag2O-TeO2 glasses with some specific compositions were prepared by quenching the melts. Studies on electrical measurements like capacitance, conductance, etc. over the frequency range 10 Hz – 1.8 GHz and in the temperature range 80K – 323K had been carried out. The concentration of mobile Ag+ ions had been estimated from analysis of the conductivity spectra using power law model and linear response theory. These results were highly important and significant for unveiling the role of AgI in the transport mechanism.

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

Research highlights of some of the proposed projects are as follows:

• Investigation of the post magnetron discharge in cylindrical version of the conventional magnetron discharge in planar geometry used in thin film deposition was carried out. In this set up, high magnetic fields were used to severely limit the electron mobility in the direction of the anode. This threw the discharge into a completely new regime which needs to be investigated thoroughly and this project aimed at carrying out such investigations.
• Some important issues pertaining to the early Universe and to Observational Cosmology would be examined. In the context of the early Universe, the viability of baryogenesis in the Next to Minimal Supersymmetric Model (NMSSM) would be checked
• Study of the structure and binding energies of drip line nuclei with neutron and proton numbers 150 and 78, 164 and 90 and 100 and 62 respectively using Infinite Nuclear Matter (INM) mass formula and RMF theory calculations.
• Possibility of construction and consequences of dual formulation of mass less and massive arbitrary spin interacting field theories was examined. Such a construction, if possible, could have significant implications for the General Theory of Relativity as well as certain versions of String Theory.
• The equation of state for hot nuclei and study of the nature of the liquid-gas phase transition that probably occurred at high temperatures have been proposed. These studies would have important implications for various astrophysical situations and for nuclear multifragmentation.

Some of the other projects include study of ECR plasma for the growth of III-V nitride: GaN; development of stellar photometric observation facility at Manipur University; supernova observations, dark energy and its identification with quintessence or vacuum energy; cosmic microwave background radiation as a probe for large-scale matter distribution and primordial magnetic fields in the universe; localized coherent excitations in (2+1) dimensional nonlinear systems; study of bottom quark decays in the Standard Model and search for physics beyond the Standard Model; star forming regions in Wolf-Rayet galaxies; investigation of interface fluid instabilities in ablatively driven multilayer targets; intermediate energy nuclear reaction cross sections and production and study of exotic nuclear states; mass function and structure of open clusters; soliton dynamics in nonlinear couplers.

Research highlights of ongoing projects are as follows :

• At IIT, Roorkee, detailed calculations on MR bands in Ce-isotopes in A=130 mass region had been done and a transition from PAC to TAC regime, induced by a triaxial to oblate shape change, had been shown for the first time. The study had shown that shape mixing effects were quite important in many MR bands.
• At IISc, Bangalore, investigations had been carried out on three important, application-oriented, topics by studying the underlying nonlinear dynamics of stick-slip namely Portevin-Le Chatelier effect; predictability of earthquakes in the context of Burridge-Knopoff model; and dynamics of peeling of adhesive tapes.
• At IACS, Kolkata, an ICPCVD facility and matching network for deposition of c-BN films had been designed, constructed and commissioned.
• At Lucknow University, work on various aspects of self-focusing with possible application of propagation of intense laser beam in the atmosphere had been carried out.
• At Aligarh Muslim University, a high-performance computing facility had been established and very good theoretical work had been done using variational Monte Carlo techniques and computer codes had been developed for studying strangeness physics of hypernuclei. Significant theoretical results had been obtained on low energy neutrino interaction which was extremely important in understanding neutrino oscillation data coming from several experiments all over the world and proposed Indian Neutrino Observatory.
• At Delhi University, a number of studies related to various scenarios of physics beyond the Standard Model had been carried out.

Lasers, Optics, Atomic and Molecular Physics

Some of the projects sanctioned in this area were as under:

• To investigate growth and studies of CLBO and related NLO crystals.
• Photonic band gap studies were planned in organics for possible applications in visible and near-IR regions.
• Studies on growth and characterisation of borate based single crystals and fabrication of SHG elements would be made in a different project.
• Theoretical studies on atom-atom scattering having relevance to Bose-Einstein Condensation and quantum systems in classical limit.
• Studies on protein profiles of clinical samples for early detection of female cancers.
• Spatio-temporal optical coherence studies would be carried out for 3D-profilometry and tomography. Research highlights of the ongoing projects are as follows:
  
• Various kinds of security holograms by i) encoding reference wave, ii) encoding holographic interferometry pattern, and iii) encoding concealed Moiré pattern were developed and investigated in detail at CSIO, Chandigarh. A simple cost effective method for making colour assigned rainbow security hologram had also been developed. Apart from these, a security hologram had been developed with an additional security measure which could be read only by using an encoded key hologram in the reading process.
• A major experimental facility for studying atomic- and molecular collisions and backscattering processes had been established at BHU, Varanasi. Energy and angular distributions of electrons ejected from CH4 and C3H8 molecules had been obtained. Polarization of K-radiation of Ar and of bremsstrahlung emitted from keV electron-Ar collision had been measured.
• A detailed theoretical analysis of all-optical light modulation characteristics of bacteriorhodopsin (bR) protein had been undertaken and all-optical spatial light modulators (SLMs), switches and logic gates had been designed at Dayalbagh Educational Institute (Deemed University), Agra.
• A software based on Split-Step-Fourier method, which was capable of solving 1-D nonlinear Schrodinger equation and modified nonlinear Schrodinger equations, had been developed at the Birla Institute of Technology, Ranchi.
• Effect of induced focusing of two laser beams in medium possessing higher order nonlinearity, particularly cubic quintic nonlinearity, had also been studied.