Synthesis and Characterization of Highly Crystalline Anatase Titania

Samarium (Sm) doped titania samples were prepared through sol–gel process by using titanium oxosulphate as precursor for titanium and samarium oxide as a precursor for Sm3+ ions. The main objective of the proposed study is to stabilize the anatase phase of titania up to high temperatures. Thermal analysis showed a weight loss of 21 % on heating up to 1000C in an inert atmosphere. IR analysis showed the complete removal of the surfactant on calcination at 500C for 2 h. The obtained samples were characterized by X-ray diffraction XRD, SEM, UV, TG-DTA & FTIR studies. It was found that the anatase phase of titania was stable up to 850C. The catalyst showed visible light absorption as evident from the UV-VIS spectrum and was found to be an active photo catalyst in sunlight

Probing CP violation in the neutrino sector with magic baseline experiments

We investigate the effect of CP violation in the leptonic sector. Due to the tiny neutrino masses its value is predicted to be very small and it is far beyond the experimental reach of the current experiments. Recently, the magic baseline experiment from CERN to INO (Indian Neutrino Observatory) with L = 7152 km has been proposed to get a sensitive limit on sin θ13. We show that due to such magic baseline neutrino beam, it is possible to observe CP violation in the neutrino sector upto several percent for the beam energy between 110 GeV

Layer-dependent electronic structures and magnetic ground states of polar-polar LaVO3/KTaO3\rm{LaVO_3/KTaO_3} (001) interfaces

Using first-principles and model Hamiltonian approach, we explore the electronic properties of polar-polar LaVO$_3$/KTaO$_3$ (LVO/KTO, 001) hetero-interfaces of up to six and five layers of KTO and LVO, respectively. Our calculations suggest the presence of multiple Lifshitz transitions (LT) in the $t_{2g}$ bands which may show up in high thermal conductivity and Seebeck coefficient. The LT can be tuned by the number of LaVO$_3$ layers or gate voltage. The spin-orbit coupling is found to be negligible, coming only from the Ta $5d_{xy}$-derived band, 5$d_{xz}$ and 5$d_{yz}$ bands being far away from the Fermi level. The magnetic properties of the interfaces, due to Vanadium ions, turn out to be intriguing. The magnetic states are highly sensitive to the number of layers of LaVO$_3$ and KTaO$_3$: the interfaces with equal number of LVO and KTO layers always favor an antiferromagnetic (AFM) ordering. Moreover, the combination of even-even and odd-odd layers shows an AFM order for more than two LaVO$_3$ layers. The spin-polarized density of states reveals that all the interfaces with ferromagnetic (FM) ground states are \textit{half-metallic}. The small energy differences between AFM and FM configurations indicate a possible coexistence of competing AFM and FM ground states in these interfaces. In addition, the interface requires different number of LVO layers for it to be metallic: half-metallic FM for three and above, and metallic AFM for four and above.Comment: 11 pages, 10 figure

Possibility of extracting the weak phase γ\gamma from Λb→ΛD0\Lambda_b \to \Lambda D^0 decays

We explore the possibility of extracting the weak phase $\gamma$ from pure tree decays $\Lambda_b \to \Lambda (D^0, \bar{D^0}, D^0_{CP})$ in a model independent way. The CP violating weak phase $\gamma$ can be determined cleanly, without any hadronic uncertainties, as these decay modes are free from the penguin pollutions. Furthermore, neither tagging nor time dependent studies are required to extract the angle $\gamma$ with these modes.Comment: 12 pages, LaTex, Minor changes in the text, version to appear in Phys. Rev.

Fluorescence dynamics of bovine serum albumin (BSA) conjugated CdZnS nanocrystallites

We report on the production of composite semiconductor CdZnS nanoparticles by adopting an inverse micellar route, using bis (2-ethylhexyl) sulfosuccinate (aerosol-AOT) as surfactant and with a degree of hydration w0=[ H2O]:[AOT]=8.9. Prior to bioconjugation (conjugation with bovine serum albumin (BSA)), the hydrophobic surface of the nanocrystals were made hydrophilic with thiol treatment (reacting with mercapto acetic acid). We compare photophysical nature of as prepared, thio-stabilized and bioconjugated CdZnS nanoparticles using absorption/emission spectroscopy and ultrafast photoluminescence decay measurements. The change-over from nonzero anisotropy (untreated) to zero anisotropy (bioconjugated) is assigned to the depolarized emission due to the surface reconstruction owing to BSA adsorption into the surface vacancies. Exploration of the dynamics of photophysical features would be promising for biomolecular sensing, labeling, and imaging applications