A5003424686- ZnO doping and properties
- Nuclear Physics and Applications
- Nuclear physics research studies
- Particle accelerators and beam dynamics
- Particle physics theoretical and experimental studies
- Gamma-ray bursts and supernovae
- Nuclear reactor physics and engineering
- Particle Accelerators and Free-Electron Lasers
- Muon and positron interactions and applications
- Quantum Chromodynamics and Particle Interactions
- Dark Matter and Cosmic Phenomena
- Copper-based nanomaterials and applications
- Astronomical Observations and Instrumentation
- Electronic and Structural Properties of Oxides
- Cosmology and Gravitation Theories
- SAS software applications and methods
- Nuclear Materials and Properties
- Superconducting Materials and Applications
- Plasma Diagnostics and Applications
- Ion-surface interactions and analysis
- Ga2O3 and related materials
- Astronomy and Astrophysical Research
- Magnetic and transport properties of perovskites and related materials
- Astronomical and nuclear sciences
- Neutrino Physics Research
Variable Energy Cyclotron Centre
2008-2019
Homi Bhabha National Institute
2018-2019
R.V. College of Engineering
2007
Visva-Bharati University
1991-1995
Room temperature ferromagnetic ordering has been observed in a rutile TiO2 polycrystalline sample after 4 MeV Ar5+ ion irradiation. The sheet resistance of the irradiated decreases from 107 to 3 × 103 Ω cm−2. Ab initio calculation density-functional theory indicates that both oxygen vacancy (VO) and titanium (VTi) can lead ferromagnetism. However, drastic lowering change colour (from white black) indicate formation VO. Experimental results along with theoretical suggest presence VO plays...
A room temperature ferromagnetic Fe doped ZnO bulk sample has been synthesized by co-doping 2 at% Mn with in ZnO. The final firing for the preparation of Zn0.96Mn0.02Fe0.02O is same as Zn0.98Mn0.02O and this case it found to be 490 °C. It that ferromagnetism a factor 1.6 times more than observed samples. size saturation magnetic field is, however, only 7 nanocrystalline undoped
Coincidence Doppler broadening of the positron annihilation technique has been employed to identify defects in thermally annealed 'as-received' ZnO and ball-milled nanocrystalline ZnO. Results indicate that a significant amount oxygen vacancy created due annealing at about 500 °C above. The results also Zn during ball milling process can be easily removed by sample defect characterization correlated with magnetic properties
The room temperature positron annihilation lifetime for single crystalline ZnO has been measured as 164 ± 1 ps. component value is very close to but higher than the theoretically predicted of ∼ 154 Photoluminescence study (at 10 K) indicates presence hydrogen and other defects, mainly acceptor related, in crystal. Defects related a lower open volume zinc vacancies, presumably complex with two atoms, are major trapping sites sample. bulk expected be little less
Low temperature photoluminescence and room positron annihilation spectroscopy have been employed to investigate the defects incorporated by 6 MeV H+ ions in a hydrothermally grown ZnO single crystal. Prior irradiation, emission from donor bound excitons is at 3.378 eV (10 K). The irradiation creates an intense narrow 3.368 intensity of this peak nearly four times that dominant near band edge pristine characteristic features indicate its origin as 'hydrogen oxygen vacancy' type defect....
Room temperature magnetic properties of 50 keV N4+ ion beam implanted rutile TiO2 have been theoretically and experimentally studied. Ab-initio calculation under the frame work density functional theory has carried out to study different possible nitrogen related defects in TiO2. Spin polarized states suggests that both Ninst NO can induce ferromagnetic ordering In cases 2p orbital electrons atom give rise moment The possibility formation N2 molecule system is also studied but this case no...
The effect of 6 MeV H+ irradiation on hydrothermally grown ZnO single crystal has been investigated using high resolution x-ray diffraction (HRXRD) and optical absorption (ultraviolet–visible) spectroscopy. increase the diffuse scattering in reciprocal space maps measured HRXRD indicates an point defect density upon irradiation. Within penetration depth x-rays several micrometres, increased with increasing distance from sample surface. On other hand, near band gap became sharper for...
A 33.7 MHz heavy-ion radio frequency quadrupole (RFQ) linear accelerator has been designed, built, and tested. It is a four-rod-type RFQ designed for acceleration of 1.38 keVu, qA> or =116 ions to about 29 keVu. Transmission efficiencies 85% 80% have measured the unanalyzed analyzed beams, respectively, oxygen ((16)O(2+), (16)O(3+), (16)O(4+)), nitrogen ((14)N(3+), (14)N(4+)), argon ((40)Ar(4+)). The system design measurements along with results beam test will be presented.
Radioactive ion beams (RIB) have been produced on-line, using a gas-jet recoil transport coupled Electron Cyclotron Resonance (ECR) ion-source at the VECC-RIB facility. atoms∕molecules carried through were stopped in catcher placed inside ECR plasma chamber. A skimmer has used to remove bulk of carrier gas entrance. The diffusion verified off-line stable isotopes and on-line transmission radioactive reaction products. Beams (14)O (71 s), (42)K (12.4 h), (43)K (22.2 (41)Ar (1.8 h) by...
A comparative study of fission actinides, especially $^{238}\mathrm{U}$, by proton and bremsstrahlung photon is performed. The relative mass distribution $^{238}\mathrm{U}$ fragments has been explored theoretically for both proton- photon-induced fission. integrated yield along with charge the products are calculated to find neutron richness in comparison nuclei produced $r$ process nucleosynthesis. Some $r$-process intermediate-mass range symmetric mode found be almost two orders magnitude...
The photonuclear reactions of actinides induced by bremsstrahlung $\ensuremath{\gamma}\text{s}$ are studied in the region nuclear excitation energies that covers entire giant dipole resonance region. A comparative analysis behavior symmetric and asymmetric modes photon-induced fission as a function average energy fissioning nucleus is performed. mass distributions for photofission fragments obtained. integrated yield well charge distribution products determined. Thus, production cross...
Prediction of the primordial abundances elements in big-bang nucleosynthesis (BBN) is one three strong evidences for big bang model. Precise knowledge baryon-to-photon ratio Universe from observations anisotropies cosmic microwave background radiation has made Standard BBN a parameter-free theory. Although, there good agreement over range nine orders magnitude between light deduced and calculated nucleosynthesis, remains yet-unexplained discrepancy $^7$Li abundance higher by factor $\sim 3$...
Abstract There is a high demand for nuclear data in multidisciplinary subject like astrophysics. The two areas of physics which are most clearly related to one another stellar evolution and nucleosynthesis. necessity astrophysical applications puts experimental methods as well reliability predicative ability current models the test. Despite recent, considerable advances, there still significant issues mysteries. Only few characteristics astrophysics covered work include $$^{52}$$ <mml:math...