Materials Literature
按标题、摘要、年份、主题和来源检索公开元数据。结果保留作者、摘要、分类与原始来源链接。
A giant electric-field-induced strain of 0.87% is reported for tetragonal (Bi0.5Na0.5)TiO3-(Bi0.5K0.5)TiO3-BaTiO3 single crystals along the [100]cubic direction, which is six times as large as that of Pb(Zr0.52Ti0.48)O3 ceramics. In situ x-ray diffraction measurements and transmission electron microscope observations…
We study the photoinduced insulator-metal transition in VO2, correlating its threshold and dynamics with excitation wavelength. In single crystals, switching can only be induced with photon energies above the 670meV gap. This contrasts with the case of polycrystalline films, where formation of the metallic state can b…
We compute the phase diagram of a biased graphene bilayer. The existence of a ferromagnetic phase is discussed with respect to both carrier density and temperature. We find that the ferromagnetic transition is first-order, lowering the value of U relatively to the usual Stoner criterion. We show that in the ferromagne…
An effective quantum parameter is obtained for the band ferromagnet in terms of orbital degeneracy and Hund's coupling. This quantum parameter determines, in analogy with 1/N for the generalized Hubbard model and 1/S for quantum spin systems, the strength of quantum corrections to spin stiffness and spin-wave energies…
Sodium ion ordering on in situ cleaved NaxCoO2 (x=0.84) surface has been studied by ultra high vacuum scanning tunneling microscopy (UHV-STM) at room temperature. Three main phases, with p(3x3), (root 7 x root 7), and (2 root 3 x 2 root 3) hexagonal unit cells and surface Na concentration of 1/3, 3/7, 1/2, respectivel…
We report the giant carrier mobility in single crystals of FeSb2. Nonlinear field dependence of Hall resistivity is well described with the two-carrier model. Maximum mobility values in high mobility band reach ∼105cm2∕Vs at 8K and are ∼102cm2∕Vs at the room temperature. Our results point to a class of materials with…
In this work, the charge transport properties of charge-ordered (CO) ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Ca}}_{x}\mathrm{Mn}{\mathrm{O}}_{3}$ $(x=0.55,0.67)$ epitaxial thin films and polycrystals are discussed following the recent controversy of localized electron states versus weakly or delocalized charge-densi…
Domain dynamics in the piezoresponse force spectroscopy (PFS) experiment is studied using the combination of local hysteresis loop acquisition with simultaneous domain imaging. The analytical theory for PFS signal from domain of arbitrary cross section and length is developed for the analysis of experimental data on P…
We study theoretically the length dependence of both conductance and thermopower in metal-molecule-metal junctions made up of dithiolated oligophenylenes contacted to gold electrodes. We find that while the conductance decays exponentially with increasing molecular length, the thermopower increases linearly as suggest…
A facile method was utilized for the construction of the bioinspired superhydrophobic Mg–Li alloy surfaces with peonylike micronanoscale hierarchical structures. The resultant materials were characterized by scanning electron microscope, x-ray photoelectron spectroscopy, and water contact angle measurements. The obtai…
Conductive hybrid carbon nanotube (CNT( films are prepared by a new and simple method. Thee graphite oxide nanoplatelet/carbon-nanotube hybrid films exhibit an extremely low square resistance. The SEM image shows the surface morphology, and reveals that one-dimensional carbon nanotubes form a conductive percolated net…
Microtribological properties of vertically-aligned carbon-nanotube (VACNT) films have been studied. Adhesion forces were obtained by measuring force-displacement curves. Friction experiments were conducted in reciprocating sliding configurations. Effects of tip radius, applied force, scan speed, and relative humidity…
A magnetic particle with atomic spins ordered in an unstable direction is an example of a false vacuum that decays via excitation of internal spin waves. Coupled evolution of the particle's magnetization (or the vacuum state) and spin waves, considered in the time-dependent vacuum frame, leads to a peculiar relaxation…
The design and fabrication of materials that exhibit both semiconducting and magnetic properties for spintronics and quantum computing has proven difficult. Important starting points are high-purity thin films as well as fundamental theoretical understanding of the magnetism. Here we show that small molecules have gre…
In this paper we show that magnetic-dipolar-mode (MDM) oscillations of a quasi-2D ferrite disk are characterized by unique symmetry features with topological phases resulting in appearance of the magnetoelectric (ME) properties. The entire ferrite disk can be characterized as a pair of two, electric and magnetic, coup…
We present an exact solution for the electrostatic field between a metallic hemi-ellipsoidal needle on a plate (as a cathode) and a flat anode. The basic idea is to replace the cathode by a linearly charged thread in a uniform electric field and to use a set of "image" charges to reproduce the anode. We calculate the…
Using first-principles density functional calculations, we study the electronic and magnetic properties of the ferromagnetic insulating double perovskite compound La2NiMnO6, which has been reported to exhibit an interesting magnetic field sensitive dielectric anomaly as a function of temperature. Our study reveals the…
The crystal structure and numerous normal and superconducting state properties of layered tetragonal $(P4∕nmm)$ LaFeAsO, with F doping of $\ensuremath{\approx}11%$, are reported. Resistivity measurements give an onset transition temperature ${T}_{c}=28.2\phantom{\rule{0.3em}{0ex}}\mathrm{K}$, and low field magnetic su…
A small percentage of platinum added to silver/gold alloys that are then electrochemically dealloyed yields an extremely high surface area nanoporous metal, with pore size less than 4 nm, as shown in the figure (scale bar = 5 nm). The presence of surface platinum stabilizes the nanostructure to coarsening in air and e…
We demonstrate the use of an ordinary white-light microscope for the study of the q-dependent dynamics of colloidal dispersions. Time series of digital video images are acquired in bright field with a fast camera, and image differences are Fourier analyzed as a function of the time delay between them. This allows for…