Materials Literature
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We demonstrate the use of Langevin spin dynamics for studying dynamical properties of an archetypical spin glass system. Simulations are performed on CuMn (20% Mn) where we study the relaxation that follows a sudden quench of the system to the low temperature phase. The system is modeled by a Heisenberg Hamiltonian wh…
We report on our investigation of the crystal structure of arsenic under compression, focusing primarily on the pressure-induced A7 to simple cubic (sc) phase transition. The two-atom rhombohedral unit cell is subjected to pressures ranging from 0 GPa to 200 GPa; for each given pressure, cell lengths and angles, as we…
Studies about the constructive aspects of noise and fluctuations in different non-linear systems have shown that the addition of external noise to systems with an intrinsic noise may result in a less noisy response. Recently, the possibility to reduce the diffusion noise in semiconductor bulk materials by adding a ran…
We predict the existence of a ferromagnetic shape memory alloy ${\text{Ga}}_{2}\text{MnNi}$ using density-functional theory. The martensitic start temperature $({T}_{M})$ is found to be approximately proportional to the stabilization energy of the martensitic phase $(\ensuremath{\delta}{E}_{\text{tot}})$ for different…
Monte Carlo simulations of the Asakura-Oosawa model for colloid-polymer mixtures confined between two parallel repulsive structureless walls are presented and analyzed in the light of current theories on capillary condensation and interface localization transitions. Choosing a polymer-to-colloid size ratio of q=0.8 an…
The magnetic properties of RMn 2 O 5 multiferroics as obtained by unpolarized and polarized neutron diffraction experiments are reviewed. We discuss the qualitative features of the magnetic phase diagram in both zero magnetic field and in field and analyze the commensurate magnetic structure and its coupling to an app…
In this article we review and discuss a mechanism for coupling between electric polarization and magnetization that can ultimately lead to electric-field switchable magnetization. The basic idea is that a ferroelectric distortion in an antiferromagnetic material can "switch on" the Dzyaloshinskii-Moriya interaction wh…
We summarize the existing experimental data on electromagnons in multiferroic RMn 2 O 5 compounds, where R denotes a rare earth ion, Y or Bi, and discuss a realistic microscopic model of these materials based on the assumption that the microscopic mechanism of magnetically induced ferroelectricity and electromagnon ab…
The symmetry properties, order parameters, and magnetoelectric phase diagrams of multiferroics are discussed. After brief reviews of Ni 3 V 2 O 8 , TbMnO 3 , and RbFe(MoO 4 ) 2 , we present a detailed analysis of RMn 2 O 5 (with R = Y, Ho, Dy, Er, Tb, Tm).
Recent progress in the design of low-melting liquid-crystalline metal complexes (metallomesogens) has facilitated the study of the photophysical properties of these compounds in the mesophase. Luminescence in the liquid crystal state has been observed for metallomesogens incorporating lanthanide(III), gold(I), silver(…
The magnetic circular dichroism of III-V diluted magnetic semiconductors, calculated within a theoretical framework suitable for highly disordered materials, is shown to be dominated by optical transitions between the bulk bands and an impurity band formed from magnetic dopant states. The real-space Green's functions…
We present high energy x-ray (67 keV) and neutron scattering measurements on a single crystal of K$_{1-x}$Li$_x$TaO$_3$ for which the Li content ($x=0.02$) is less than $x_c = 0.022$, the critical value below which no structural phase transitions have been reported in zero field. While the crystal lattice does remain…
The material presented here is supplementary to the article entitled: "Density-functional investigation of the rhombohedral to simple cubic phase transition of arsenic"; it deals with the convergence issues involved in studying a semi-metal to metal structural phase transition such as the A7 to sc transition of arseni…
We find, with the use of first-principles calculations, that a single-atom-thick boron-nitride (BN) sheet exhibits an unusual nonlinear electromechanical effect: it becomes macroscopically polarized when bent out-of-plane. The direction of the induced polarization is in the plane of the film and it depends non-analiti…
Abstract Wheat straw was liquefied in the mixture of polyethylene glycol (PEG 400) and glycerin in the presence of acid at the temperature 130–160°C. The final liquefaction products having the hydroxyl number of 250–430 mg KOH/g and the $ \overline M_n $ of about 1050 can be used as the polyol component to manufacture…
Effective growth of multiwalled boron nitride nanotubes (BNNTs) has been obtained by thermal chemical vapor deposition (CVD). This is achieved by a growth vapor trapping approach as guided by the theory of nucleation. Our results enable the growth of BNNTs in a conventional horizontal tube furnace within an hour at 12…
A new quaternary fluoroarsenide CaFeAsF with the tetragonal ZrCuSiAs-type structure composed of alternate stacking of (FeAs)delta- and (CaF)delta+ layers was synthesized. CaFeAsF is a poor metal and shows the anomaly at approximately 120 K in temperature dependence of electrical conductivity. The electron doping by th…
Redox polymer layers with 2,2,6,6-tetramethylpiperidin-1-oxyl-4-yl (TEMPO) groups showed nernstian adsorbate-like electrochemical behaviors up to submicrometer thicknesses, based on a fast charge propagation within the bulk layer and persistency in electrolyte solutions.
The symmetry conditions for the occurrence in a same phase of one or more of the four primary ferroic properties, i.e., ferroelectricity, ferromagnetism, ferrotoroidicity and ferroelasticity, are discussed. Analogous conditions are outlined for the admission of so-called secondary and tertiary ferroic effects, such as…
In this paper, we review the recent research on the functionalization of multiferroics for spintronics applications. We focus more particularly on antiferromagnetic and ferroelectric BiFeO 3 and its integration in several types of architectures. For instance, when used as a tunnel barrier, BiFeO 3 allows the observati…