Fe2Al5 contains a Fe-Al matrix through which are threaded disordered one-dimensional chains of overlapping Al sites. We report magnetic, nuclear-magnetic-resonance (NmR), and specific-heat measurements addressing its ...
Fe2Al5 contains a Fe-Al matrix through which are threaded disordered one-dimensional chains of overlapping Al sites. We report magnetic, nuclear-magnetic-resonance (NmR), and specific-heat measurements addressing its magnetic and vibrational properties. The Curie-type susceptibility is found to be due to dilute moments, likely due to wrong-site Fe atoms. A27l NmR shift and spin-lattice relaxation measurements confirm these to be indirectly coupled through a Ruderman-Kittel-Kasuya-Yoshida-type interaction. Specific-heat results indicate a large density of low-energy vibrational modes. These excitations generate a linear-T contribution to the specific heat, which however freezes out below about 10 K. These results are attributed to the presence of anharmonic vibrational modes associated with the disordered structural chains.
We have synthesized type-VIII and type-I Ba8Ga16Sn30 clathrates by using different annealing treatments, confirmed with XRD and electron microprobe measurements. NmR lineshape measurements identified a broad resonance...
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We have synthesized type-VIII and type-I Ba8Ga16Sn30 clathrates by using different annealing treatments, confirmed with XRD and electron microprobe measurements. NmR lineshape measurements identified a broad resonance corresponding to first-order-shifted satellites. Simulations for the type I structure based on first principles calculations provided an excellent fit to the data, with the best agreement provided by the calculated lowest-energy configuration, having no Ga-Ga bonds. These results allow us to address local configurations within the random type-I alloy, as well as atomic displacements and bond-length distributions, which we compare to experiment.
monodisperse ZnO quantum dots (QDs) with a particle size of about 5 nm have been synthesized. Isopropanol together with hexane were utilized to precipitate ZnO nanoparticles to form condensed phases, ranging from whit...
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Enzymatic glucose sensors based on luminescent microparticles rely on the reaction of glucose and oxygen with glucose oxidase, where the internal oxygen level is transduced via oxygen-sensitive phosphors. These sensor...
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Enzymatic glucose sensors based on luminescent microparticles rely on the reaction of glucose and oxygen with glucose oxidase, where the internal oxygen level is transduced via oxygen-sensitive phosphors. These sensors utilize nanofilm coatings comprising polyelectrolyte multilayers deposited using self-assembly to control transport of glucose, enabling tuning of the range and sensitivity by changing the coating thickness. In this work, it was also found that salt concentrations, which influence thickness and density of nanofilm coatings during multilayer deposition, also influence range, sensitivity, and degradation rate of these sensors.
A systematic study to investigate the effectiveness of ion implanted N+ as a dopant for ZnO and a co-dopant in silver doped ZnO (ZnO:Ag, SZO) thin films was performed. ZnO and SZO films were grown on sapphire (0001)
A systematic study to investigate the effectiveness of ion implanted N+ as a dopant for ZnO and a co-dopant in silver doped ZnO (ZnO:Ag, SZO) thin films was performed. ZnO and SZO films were grown on sapphire (0001)
Exact extended traveling wave and spatiotemporal soliton solutions to the generalized (3+1)-dimensional Gross-Pitaevskii equation with time-dependent coefficients are obtained. The case with constant diffraction and p...
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Exact extended traveling wave and spatiotemporal soliton solutions to the generalized (3+1)-dimensional Gross-Pitaevskii equation with time-dependent coefficients are obtained. The case with constant diffraction and parabolic potential strength, but with variable gain, is discussed in some detail. It is found that gain in the system is necessary for the appearance of stable solitons.
Presented is a study of uncompensated magnetization in antiferromagnets performed by SQUID and VSmmagnetometry, and polarized neutron reflectometry. This uncompensated magnetization is observed and studied as a funct...
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For molecules and materials responding to femtosecond-scale optical laser pulses, we predict maximum relative excitation of a Raman-active vibrational mode with period T when the pulse has a full-width-at-half-maximum...
For molecules and materials responding to femtosecond-scale optical laser pulses, we predict maximum relative excitation of a Raman-active vibrational mode with period T when the pulse has a full-width-at-half-maximum duration τ≈0.42T. This result follows from a general analytical model, and is precisely confirmed by detailed density-functional-based dynamical simulations for C60 and a carbon nanotube, which include anharmonicity, nonlinearity, no assumptions about the polarizability tensor, and no averaging over rapid oscillations within the pulse. The mode specificity is, of course, best at low temperature and for pulses that are electronically off-resonance, and the energy deposited in any mode is proportional to the fourth power of the electric field.
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