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The Eu3+ doped phosphate based phosphors NaCdPO4 hosts were prepared by solid-state reaction. The effects of the crystalline host and the incorporation of a sensitizer Eu3+ on the luminescence characteristics of the specimen phosphors were studied. NaCdPO4 was investigated for its structural and luminescence properties, as a possible host material for efficient phosphors. Prepared phosphors were characterized by photoluminescence technique possesses a 320 nm excitation maxima and emission broad peak appears at 637 nm indicating a possible red phosphor for UV excitation operated white LED application. [ABSTRACT FROM AUTHOR]

Physical properties are known to be drastically varied with chemical pressure and crystallite size in a multifunctional material. In this context, various concentrations of Zn (0 ≤ x ≤ 0.2) in the Fe site of LaFeO3 are prepared by wet-chemical route. The average particle size is of the order of 40-50 nm. The concentration dependent electrical behavior and the conduction mechanism at room temperature have been studied in detail by cole-cole plot of the Impedance and modulus spectra. The high frequency depressed semi circles represent the grain conduction while the intermediate frequency semi circles appear may be due to grain boundary effect. [ABSTRACT FROM AUTHOR]

Detailed magnetic measurements of the Pr0.75Na0.25MnO3 polycrystalline sample have been carried out under external hydrostatic pressure upto 10kbar. Pressure strongly suppresses the first order magnetic transition, while thermal hysteresis narrows down progressively and then disappears with increase in pressure. The significant enhancement of the field cooled magnetization value at different pressures is due to the antiferromagnetic to ferromagnetic transformation, while ruling out any contribution from the domain alignment within the ferromagnetic phase. [ABSTRACT FROM AUTHOR]

Modified-PZT ceramics with a formula Pb0.9Ni0.1[(Zr0.52Ti0.48)]1-xSnxO3 located near the morphotropic phase boundary (MPB) were prepared by conventional solid state process to investigate effects of dilute doping of Ni and Sn in different sites of PZT. The single phase structure of the series of samples has been identified by x-ray diffraction technique. The optical band gap has been obtained from the UV-Vis spectra and found to be shrinkage with doping. The detail dielectric and impedance studies are being carried out to investigate the conduction mechanism of the samples. A significant enhancement in the electric polarization is observed for the maximum Sn doping in a modified PZT. [ABSTRACT FROM AUTHOR]

Simultaneous measurement of field dependent resistivity and dielectric permittivity has been carried out to observe the tunability of magnetoelectric phases of contrasting order in a charge order material Pr0.75Na0.25MnO3. The material is synthesized by wet chemical technique to reduce the volatilization of Na and avoid any precipitation of manganese oxide. The dielectric study reveals highly resistivity correlated dielectric behavior has been observed throughout the insulator to metal and vice versa transition. The metallic phase in the proximity of insulating phase enhances the functionality of this material with a several order in the magnetoelectric parameter. Furthermore, the Maxwell-Garnett theory is being used to analyze the field and temperature dependent dielectric anomaly. [ABSTRACT FROM AUTHOR]

Total fusion (TF) excitation function has been measured for the system 7Li + 64Ni at the energies near the Coulomb barrier of the system. The evaporation residue (ER) cross sections have been estimated through the online detection of characteristic γ-rays of the ERs. The summed ER cross sections yielding the experimental TF cross section have been compared with the theoretical one dimensional barrier penetration model (1DBPM) prediction. The measured and the model cross sections are very close to each other at above barrier energies. However, an enhancement of the experimental TF cross section with respect to the 1DBPM prediction is observed at below barrier energies. Coupled channels (CC) calculation with inelastic excitations alone could not explain the enhancement. The origin of the enhancement is identified as due to the enhanced population of the αxn channels. [ABSTRACT FROM AUTHOR]

Total fusion excitation function has been measured for the reaction of weakly bound 6Li projectile on medium mass 64Ni target at energies near the Coulomb barrier of the system. Online characteristic γ-ray detection method has been used to identify and determine the cross sections of the residues. No suppression of total fusion cross section (σTF) is observed at above barrier energies. But enhancement of measured cross section with respect to the one-dimensional barrier penetration model (1-DBPM) calculation is observed at below barrier energies. The enhancement can not be explained by coupled channels calculation with dominant projectile and target excitations as well as one-neutron stripping reaction. [ABSTRACT FROM AUTHOR]

To study the effect of breakup coupling on fusion we have derived fusion cross sections in the framework of continuum discretised coupled channels (CDCC) method using the coupled channels code FRESCO for the systems 6,7Li+24Mg. The CDCC predicted fusion cross sections for the 7Li+24Mg system agree well with the experimental fusion data whereas for the 6Li+24Mg system the agreement is reasonable at below barrier energies. However, within the limits of the present work no definite conclusion could be obtained from the quality of agreement at above barrier energies for the 6Li+24Mg system. [ABSTRACT FROM AUTHOR]

The CaCu3Ti4O12 (CCTO) remains as the best material for practical applications due to its high dielectric constant. To improve further the dielectric properties of CCTO to several orders in magnitude, a novel approach is adopted by codoping of Sr, Sb ions. The ceramic samples were fabricated by the conventional solid state route. The structure, morphology and detail dielectric properties were investigated systematically. All the samples crystalizes in a cubic symmetry with Im-3 space group. Sr substituted in Ca site can effectively suppress the grain growth, achieving a fine grained ceramic structure; however the grain size decreased slightly as Sb concentration increased further; whereas the dielectric permittivity of the ceramics increased drastically. The giant dielectric response was considered to be closely related with a reduction in the potential barrier height at grain boundaries (GBs) supported by the reduction in the activation energy for the conduction process. [ABSTRACT FROM AUTHOR]

Physical properties are known to be drastically varied with crystallite size and in a multifunctional material this size reduction is seem to be interesting. One such material is chosen as LaFeO3 nanoparticles which have been prepared by wet-chemical route. The average particle size found to be in the order of 45nm in which the chemical content of the unit cell has been verified. A distorted orthorhombic structure with Pbnm space group is possessed by this nanoparticle. From the bifurcation of ZFC and FC in low field, behavior of inverse susceptibility and the small hysteresis loop favors the material to be in a weak FM state well below the Neel temperature. The electrical behavior and the conduction mechanism above room temperature have been studied by cole-cole plot of the Impedance spectra. The high frequency depressed semi circles represent the grain conduction while the intermediate frequency semi circles appear may be due to grain boundary effect. [ABSTRACT FROM AUTHOR]