Materials Literature
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We have investigated the properties of Zn1−xMnxO (x=0.01–0.1) thin films grown on c-plane sapphire single crystals by pulsed laser deposition. The electrical, magnetic, optical, and microstructural properties of these thin films have been characterized systematically, with a primary focus on establishing a correlation…
Nanocrystalline Ce1−xRExO2−y (RE=La and Nd) powders were synthesized with a controlled size in the range of 3–5nm using microemulsion technique. The nanoceria retains its cubic fluorite structures for the complete doping range. X-ray diffraction and Raman spectroscopic studies showed that the lattice distortion increa…
The dielectric properties of MnFe2O4 and γ-Fe2O3 magnetic nanoparticles embedded in insulating matrices were investigated. The samples showed frequency dependent dielectric anomalies coincident with the magnetic blocking temperature and significant magnetocapacitance above this blocking temperature, as large as 0.4% a…
The self-organized dopant percolative filamentary model, entirely orbital in character (no spins), is strongly influenced by background (in)homogeneities. In the high temperature superconductive (HTSC) cuprates, pseudogap regions produce novel percolative features in phase diagrams. The model is especially successful…
Silica skeletal architectures in diatoms are characterized by remarkable morphological and nanostructural details. Silk proteins from spiders and silkworms form strong and intricate self-assembling fibrous biomaterials in nature. We combined the features of silk with biosilica through the design, synthesis, and charac…
We study the effects of long and short-range electron-electron interactions in a graphene bilayer. Using a variational wave function technique we show that in the presence of long-range Coulomb interactions the clean bilayer is always unstable to electron and hole pocket formation with a finite ferromagnetic polarizat…
Polycrystalline Mn-doped, Nb-doped, and pure BiFeO3 (BFO) films were fabricated via chemical solution deposition (CSD) method. Influence of Mn and Nb dopants on electric properties of BFO films were studied. The current density versus electric field (J-E) characteristics indicated that conduction mechanisms of Mn-dope…
We have grown epitaxial BiFeO3 thin films with smooth surfaces on (001), (101), and (111) SrTiO3 substrates using sputtering. Four-circle x-ray diffraction and cross-sectional transmission electron microscopy show that the BiFeO3 thin films have rhombohedral symmetry although small monoclinic distortions have not been…
Abstract Advances in nanotechnology research on quantum dots (QDs)—water soluble ZnS‐capped, CdSe fluorescent semiconductor nanocrystals—for in vivo biomedical applications have prompted a close scrutiny of the behavior of nanostructures in vivo. Data pertaining to pharmacokinetics and toxicity will undoubtedly assist…
The annealing effects on structure and magnetism for Co-doped ZnO films under air, Ar, and Ar∕H2 atmospheres at 250°C have been systematically investigated. Room-temperature ferromagnetism has been observed for the as-deposited and annealed films. However, the saturation magnetization (Ms) varied drastically for diffe…
Results are presented for ZnO-based ultraviolet light emitting diodes (LEDs) that employ a BeZnO∕ZnO active layer comprised of seven quantum wells. Arsenic and gallium are used for p-type and n-type layers. The ZnO-based LEDs show two dominant electroluminescence peaks located in the ultraviolet spectral region betwee…
Magnetoelectric and magnetoelastic phenomena have been investigated on a frustrated triangular antiferromagnetic lattice in $\mathrm{Cu}\mathrm{Fe}{\mathrm{O}}_{2}$. Inversion-symmetry breaking, manifested as a finite electric polarization, was observed in noncollinear (helical) magnetic phases and not in collinear ma…
It has been known for more than half a century that crystals can be made stronger by introducing defects into them, i.e., by strain-hardening. As the number of defects increases, their movement and multiplication is impeded, thus strengthening the material. In the present work we show hardening by dislocation starvati…
The metallo-glycerophosphodiesterase from Enterobacter aerogenes (GpdQ) has been cloned, expressed in Escherichia coli and purified. Initial screening of crystallization conditions for this enzyme resulted in the identification of needles from one condition in a sodium malonate grid screen. Removal of the metals from…
The synthesis of polyolefins with two metallocene catalysts is explored via a simple Monte Carlo simulation in the two cases of a batch and a semibatch reactor. The algorithm we develop can be applied, in principle, to an arbitrary number of catalysts with different propensities toward the formation of long chain bran…
Abstract Well-dispersed organic nanoparticles of porphyrin with narrow size distribution were successfully prepared in aqueous solution based on the “ion-association” method. No self-aggregation of the constituent porphyrin chromophores was confirmed. The nanoparticles exhibit interesting optical properties; a large b…
The perovskite phase nucleation and growth of Ba 0.8 Sr 0.2 TiO 3 [BST(80/20)] films was restricted to the bottom interface by the use of a Ba 0.8 Sr 0.2 TiO 3 [BST(80/20)] sol−gel seed layer of optimized thickness. As a result ( h 00) preferred orientation, BST thin films on Pt/Ti/SiO 2 /Si with enhanced electric pro…
We have performed systematic ab initio calculations to study the structures and stability of Si(6)O(n)() clusters (n = 1-12) in order to understand the oxidation process in silicon systems. Our calculation results show that oxidation pattern of the small silicon cluster, with continuous addition of O atoms, extends fr…
Small-angle X-ray scattering, depolarized light scattering, and transmission electron microscopy were used to study the dependence of structure and thermodynamics on cross-linking of a symmetric poly(styrene- block -isoprene) copolymer. The polyisoprene block was cross-linked well above the order−disorder transition (…
Aggregation of thiol-stabilized silver nanoparticles induced by 1,6-hexane dithiol was studied in situ by dynamic light scattering. The aggregates were observed to reach a finite size in the 100-200 nm range depending on the applied conditions. Growth kinetics were shown to be linked to the dynamics of the thiol-excha…