Materials Literature
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We report the first direct transition from a paramagnetic and paraelectric phase to an incommensurate multiferroic in the triangular lattice antiferromagnet RbFe(MoO4)(2). Ferroelectricity is observed only when the magnetic structure has chirality and breaks inversion symmetry. A Landau expansion of symmetry-allowed t…
Band gap studies of zigzag-edge graphene ribbons are presented. While earlier calculations at LDA level show that zigzag-edge graphene ribbons become half-metallic when cross-ribbon electric fields are applied, our calculations with hybrid density functional demonstrate that finite graphene ribbons behave as half-semi…
The synthesis, characterization, and field-effect transistor (FET) properties of new indolo[3,2-b]carbazoles are described. In particular, an extensive characterization of their crystal structures has revealed the importance of the nature of the side chains (alkyl, phenyl, thienyl substituents) on their solid-state or…
Core/multishell-structured semiconductor nanocrystals (NCs) are prepared in multigram amounts through a one-pot process without a core-separation step (see figure and cover). The NCs show a maximum quantum efficiency of 85 % at a controlled wavelength and strong photostability against UV-light bleaching. The NCs are a…
Solid-stabilized, or Pickering, miniemulsion polymerizations using Laponite clay discs as stabilizer are investigated. Free radical polymerizations are carried out using a variety of hydrophobic monomers (i.e., styrene, lauryl (meth)acrylate, butyl (meth)acrylate, octyl acrylate, and 2-ethyl hexyl acrylate). Armored l…
Recent experimental work on locally gated graphene layers resulting in p-n junctions has revealed the quantum Hall effect in their transport behavior. We explain the observed conductance quantization, which is fractional in the bipolar regime and an integer in the unipolar regime, in terms of quantum Hall edge modes p…
The entire zone-center phonon spectrum of the $R3c$ ferroelectric antiferromagnetic phase of bismuth ferrite is computed using a first-principles approach based on density functional theory. Two phonon modes exhibiting eigendisplacement vectors that strongly overlap with the atomic distortions taking place at the ferr…
The unique band structure of graphene allows reconfigurable electric-field control of carrier type and density, making graphene an ideal candidate for bipolar nanoelectronics. We report the realization of a single-layer graphene p-n junction in which carrier type and density in two adjacent regions are locally control…
Electron spin resonance (ESR) in polycrystalline diamond films grown by dc arc-jet and microwave plasma chemical vapour deposition is studied. The films with nitrogen impurity concentration up to 8 × 10 18 cm −3 are also characterized by Raman, cathodoluminescence and optical absorption spectra. The ESR signal from P1…
A new empirical model to estimate the content of sp 3 in diamond-like carbon (DLC) films is presented, based on the conventional Raman spectra excited by 488 nm or 514 nm visible light for different carbons. It is found that bandwidth of the G peak is related to the sp 3 fraction. A wider bandwidth of the G peak shows…
Laser-ablated sodium atom reactions with H2 have been investigated in solid molecular hydrogens and neon. The NaH molecule and (NaH)2,3,4 clusters were identified by IR spectra with isotopic substitution (HD and D2) and comparison to frequencies calculated by density functional theory and the MP2 method. The use of pa…
Abstract Generation of dislocations during the growth of oxygen precipitates has been used as an alternative way of introduction of dislocation‐related luminescence centers. For this purpose a multistep annealing of Cz Si samples with different initial concentrations of oxygen has been carried out. The analysis of def…
Magnetic diffusion time in nonlinear steel is shown to vary with applied field magnitude and whether the field is undergoing infusion (inward flow upon turnon) or effusion (outward flow upon turnoff). Transient finite-element analysis is used to compute planar flux effusion that agrees very closely with an analytical…
We investigate the configurations, electronic structures, and magnetic ordering of Mn N ( N = 2–13) clusters based on all-electron density functional theory. The Jahn–Teller effect plays an important role in determining the ground state of certain geometries. The magnetic ordering of the Mn N clusters transits from fe…
Poly(carbonate urethane)s (PCUs) are usually considered as biostable elastomers for long-term implantation. However, their hydrolytic stability is still questionable. The biodegradation appears to be initiated by oxidative and hydrolytic substances released by inflammatory cells. Therefore, the biostability of polyure…
Measurements of magnetization, electrical resistivity, and synchrotron x-ray diffraction were performed on single crystals of ${\mathrm{Bi}}_{1\ensuremath{-}x}{\mathrm{Sr}}_{x}\mathrm{Mn}{\mathrm{O}}_{3}$ $(0.35\ensuremath{\leqslant}x\ensuremath{\leqslant}0.64)$. The resistivity and magnetization curves show a kink ne…
Effects of different mineral acids (viz. H 2 SO 4, H 3 PO 4, HNO 3, HCl, HBr, and HI), acid (H 3 PO 4 ) concentration, different halide anions (viz. F -, Cl -, Br -, and I - ), and halide anion concentration in aqueous reaction medium on the H 2 O 2 formation (in H 2 -to-H 2 O 2 oxidation) and/or on the H 2 O 2 destru…
Heart valve replacement represents the most common surgical therapy for end-stage valvular heart diseases. A major drawback all contemporary heart valve replacements have in common is the lack of growth, repair, and remodeling capabilities. To overcome these limitations, the emerging field of tissue engineering is foc…
Cr-doped InAs self-organized diluted magnetic quantum dots (QDs) are grown by low-temperature molecular-beam epitaxy. Magnetic measurements reveal that the Curie temperature of all the InAs:Cr QDs layers with Cr/In flux ratio changing from 0.026 to 0.18 is beyond 400 K. High-resolution cross sectional transmission ele…
A conjugated diyne monomer (A) was prepared by linking two acetylenic triple bonds together by a biphenyl bridge and its copolycyclotrimerizations with (E)-2-( 1-ferrocenyl)vinyl-p-phenylacetylene (B) was investigated, in an effort to synthesize ferrocene-containing hyperbranched conjugated polymers. The conjugated st…