Materials Literature
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Direct hysteresis measurements on single submicron structure sizes were performed on epitaxial ferroelectric Pb(Zr,Ti)O3 thin films grown on SrTiO3 with La0.5Sr0.5CoO3 (LSCO) electrodes. The samples were fabricated by focused-ion-beam milling resulting in pad sizes down to 200 nm×200 nm. The influence of parasitic cap…
Nanocrystalline Er-doped CeO2 phosphors with an average crystallite size of 18, 38, and 70 nm were prepared by glycine–nitrate solution combustion synthesis. The particle size of the resultant powders is tied up with the combustion flame temperature, which can be controlled by adjusting the ratio of glycine to nitrate…
The influence of dc current flow on the resistivity and phase transitions in low-doped ${\mathrm{La}}_{0.82}{\mathrm{Ca}}_{0.18}{\mathrm{MnO}}_{3}$ single crystals has been investigated. At low temperatures, where the resistivity strongly increases with decreasing temperature, dc current depresses resistivity in a way…
Isothermal annealing of two partially metamict zircon from Sri Lanka were carried out at 870 K, 968 K, 1071 K, and 1166 K for 0.5 min up to ∼; 210 hours. Raman spectroscopy was used to monitor the amorphous-to-crystalline transformation. The evolution of the phonon frequency and the linewidth of the v 3 Si-O stretchin…
Evidence has been found for a change in the ordered occupation of the vanadium d orbitals at the 77 K phase transition in YVO3, manifested by a change in the type of Jahn-Teller distortion. The orbital ordering above 77 K is not destroyed at the magnetic ordering temperature of 116 K, but is present as far as a second…
Crystallization processes in different Te alloys, employed in phase change materials for optical data storage, have been investigated by in situ mechanical stress measurements. Upon crystallization a considerable stress buildup is observed, which scales with the volume change upon crystallization. Nevertheless the obs…
A magnetoresistance study of carbon nanotubes demonstrates that, for small diameters, the location of the chemical potential and the orientation of the magnetic field are parameters that enable tuning from positive to negative magnetoresistance, a phenomenon not related with weak localization. For larger diameters (>…
The complex dielectric functions of wurtzite ZnS thin films grown on (0001) Al2O3 have been determined by using spectroscopic ellipsometry over the spectral range of 1.33–4.7 eV. Below the band gap, the refractive index n is found to follow the first-order Sellmeir dispersion relationship n2(λ)=1+2.22λ2/(λ2−0.0382). S…
Experimental measurements of Raman spectra for hcp iron at high pressure show two modes over a considerable pressure range in contrast to the prediction of one doubly degenerate mode for the hcp lattice. We use density functional theory to investigate the influence of magnetic order on the Raman active modes of hcp ir…
We report the discovery of a new class of molecular phases of solid nitrogen at high pressures and temperatures by Raman and infrared spectroscopy and powder x-ray diffraction. Unlike the molecular phases consisting of disk- and sphere-like molecular disorder ($δ$-, $ε$- and $ζ$-N$_2$) and reportedly stable over a wid…
The spin-polarized scanning tunnelling microscope (STM) can in principle resolve not only the electronic, but also the magnetic surface structure. We model recent STM measurements achieving magnetic resolution on the atomic scale by a first-principles method. It is shown that the signature of a specific magnetic or no…
Spin relaxation time of conduction electrons through the Elliot-Yafet, D'yakonov-Perel and Bir-Aronov-Pikus mechanisms is calculated theoretically for bulk GaAs, GaSb, InAs and InSb of both $n$- and $p$-type. Relative importance of each spin relaxation mechanism is compared and the diagrams showing the dominant mechan…
We have performed the most realistic simulation to date of the operation of a scanning tunneling microscope. Probe-sample distances from beyond tunneling to actual surface contact are covered. We simultaneously calculate forces, atomic displacements, and tunneling currents, allowing quantitative comparison with experi…
In this paper the fabrication process for a screen-printable magnetostrictive thick-film material based upon the giant magnetostrictive material, Terfenol-D, is reported. Factors affecting the magnetostriction of the printed thick film have been identified, and suitable parameters selected to yield a functional thick…
Two 2D coordination polymers [M(NCS)2(pzdo)2] (M = Mn, Co; pzdo = pyrazine dioxide) bridged by pzdo ligand are synthesized, which are found to exhibit antiferromagnetic ordering below 8.4 and 11.2 K, respectively.
Hexagonal boron nitride films on Si(100) substrates are formed from the system N2/B(OCH3)3 (TMOB) by microwave plasma enhanced chemical vapour deposition (PECVD). The parameters substrate temperature, deposition time and composition of the process gas mixture were varied. The stability of the deposited layers mainly d…
Acetylene-substituted tetra[6,7]quinoxalinoporphyrazines, obtained in two steps from dialkynyl-1,2-diones and 1,2-diamino-4,5-dicyanobenzene, show intense absorptions in the near infrared and have photooxidising properties that make them promising candidates as agents active in photodynamic therapy.
Floating drops of magnetic fluid can be brought into rotation by applying a rotating magnetic field. We report theoretical and experimental results on the transition from a spheroid equilibrium shape to non-axissymmetrical three-axes ellipsoids at certain values of the external field strength. The transitions are cont…
We have assigned the chirality of the internal tubes of double walled carbon nanotubes grown by catalytic chemical vapor deposition using the high sensitivity of the radial breathing mode (RB) in inelastic light scattering experiments. The deduced chirality corresponds to several semiconducting and only two metallic i…
>From magnetic storage to catalysts, the useful properties of many materials can be traced back to the presence of metallic elements. But introducing metals into polymers has been a synthetic challenge. In his Perspective, Manners describes recent progress toward polymers in which metallic elements act as structural c…