Size driven barrier to chirality reversal in electric control of magnetic vortices in ferromagnetic nanodiscs.

New high density storage media and spintronic devices come about with a progressing demand for the miniaturization of ferromagnetic structures. Vortex ordering of magnetic dipoles in such structures has been repeatedly observed as a stable state, offering the possibility of chirality in these states as a means to store information at high density. Electric pulses and magnetoelectric coupling are attractive options to control the chirality of such states in a deterministic manner.

Vapor phase synthesis of ferroelectric microislands on PVDF thin films.

The interest in patterned polyvinylidene fluoride (PVDF) surfaces has grown significantly in the recent years due to ability to control the ferroelectric behavior through the size and shape of the surface structures. However, forming micron sized structures on the PVDF surface generally requires laborious lithography based methods or use of templates which complicates the process. In this study, we report spontaneous formation of microislands with ferroelectric response during PVDF growth via initiated chemical vapor deposition.

Synthesis and Morphological Control of VO Nanostructures via a One-Step Hydrothermal Method.

The morphology of nanostructures is a vital parameter to consider in components comprised of materials exhibiting specific functionalities. The number of process steps and the need for high temperatures can often be a limiting factor when targeting a specific morphology. Here, we demonstrate a repeatable synthesis of different morphologies of a highly crystalline monoclinic phase of vanadium dioxide (VO(M)) using a one-step hydrothermal method.

A Theoretical Treatment of THz Resonances in Semiconductor GaAs p-n Junctions.

Semiconductor heterostructures are suitable for the design and fabrication of terahertz (THz) plasmonic devices, due to their matching carrier densities. The classical dispersion relations in the current literature are derived for metal plasmonic materials, such as gold and silver, for which a homogeneous dielectric function is valid. Penetration of the electric fields into semiconductors induces locally varying charge densities and a spatially varying dielectric function is expected.

Distribution of non-lumbricid earthworms (Clitellata: Acanthodrilidae, Criodrilidae, Megascolecidae and Ocnerodrilidae) on the Balkans and Anatolia with first record of Amynthas morrisi (Beddard, 1892) from Turkey.

Based on previous and on new species records, the non-lumbricid earthworm fauna of the Balkans and Anatolia consists of ten species, belonging to four families: Acanthodrilidae, with Microscolex dubius (Fletcher, 1886) and Microscolex phosphoreus (Dugès, 1837), Criodrilidae, with Criodrilus lacuum Hoffmeister, 1845 and Criodrilus ochridensis Georgevitch, 1950, Megascolecidae, with Amynthas corticis (Kinberg, 1867), Amynthas gracilis (Kinberg, 1867), Amynthas morrisi (Beddard, 1892), Metaphire californica (Kinberg, 1867), and Pontodrilus litoralis (Grube, 1855), and Ocnerodrilidae, with Ocnerodrilus occidentalis Eisen, 1878. Four species are recorded on the both territories (C. lacuum, M.

Earthworms from Bursa Uludağ Mountain, with first record of Octolasion cyaneum (Savigny, 1826) from Turkey.

Uludağ is the highest mountain (2.543 m) of the Marmara region in Bursa Province, western Turkey. The Uludağ National Park has rich biodiversity in terms of fauna and flora.

Monitoring the Damage State of Fiber Reinforced Composites Using an FBG Network for Failure Prediction.

A structural health monitoring (SHM) study of biaxial glass fibre-reinforced epoxy matrix composites under a constant, high strain uniaxial fatigue loading is performed using fibre Bragg grating (FBG) optical sensors embedded in composites at various locations to monitor the evolution of local strains, thereby understanding the damage mechanisms. Concurrently, the temperature changes of the samples during the fatigue test have also been monitored at the same locations. Close to fracture, significant variations in local temperatures and strains are observed, and it is shown that the variations in temperature and strain can be used to predict imminent fracture.

Tunable Surface Plasmon and Phonon Polariton Interactions for Moderately Doped Semiconductor Surfaces.

Spatial charge distribution for biased semiconductors fundamentally differs from metals since they can allow inhomogeneous charge distributions due to penetration of the electric field, as observed in the classical Schottky junctions. Similarly, the electrostatics of the dielectric/semiconductor interface can lead to a carrier depletion or accumulation in the semiconductor side when under applied bias. In this study, we demonstrate that the inhomogeneous carrier accumulation in a moderately p-doped GaAs-dielectric interface can be tailored for tunable plasmonics by an external voltage.

Domain control of carrier density at a semiconductor-ferroelectric interface.

Control of charge carrier distribution in a gated channel via a dielectric layer is currently the state of the art in the design of integrated circuits such as field effect transistors. Replacing linear dielectrics with ferroelectrics would ultimately lead to more energy efficient devices as well as the added advantage of the memory function of the gate. Here, we report that the channel-off/channel-on states in a metal/ferroelectric/semiconductor stack are actually transitions from a multi domain state to a single domain state of the ferroelectric under bias.

Influence of long-range dipolar interactions on the phase stability and hysteresis shapes of ferroelectric and antiferroelectric multilayers.

Phase transition and field driven hysteresis evolution of a two-dimensional Ising grid consisting of ferroelectric-antiferroelectric multilayers that take into account the long range dipolar interactions were simulated by a Monte-Carlo method. Simulations were carried out for a 1 + 1 bilayer and a 5 + 5 superlattice. Phase stabilities of components comprising the structures with an electrostatic-like coupling term were also studied.