Influence of interface structure on electronic properties and Schottky barriers in Fe/GaAs magnetic junctions

The electronic and magnetic properties of Fe/GaAs(001) magnetic junctions are investigated using first-principles density-functional calculations. Abrupt and intermixed interfaces are considered, and the dependence of charge transfer, magnetization profiles, Schottky barrier heights, and spin polarization of densities of states on interface structure is studied. With As-termination, an abrupt interface with Fe is favored, while Ga-terminated GaAs favors the formation of an intermixed layer with Fe. The Schottky barrier heights are particularly sensitive to the abruptness of the interface. A significant density of states in the semiconducting gap arises from metal interface states. These spin-dependent interface states lead to a significant minority spin polarization of the density of states at the Fermi level that persists well into the semiconductor, providing a channel for the tunneling of minority spins through the Schottky barrier. These interface-induced gap states and their dependence on atomic structure at the interface are discussed in connection with potential spin-injection applications.Comment: 9 pages, 9 figures, to appear in PR

Спектр та динаміка живлення бичка кругляка Neogobius melanostomus (Pallas, 1814) у Білосарайській затоці Азовського моря

Paper deals with round goby’s diet composition and its daily feeding changes on the Belosaraiskа Bay were analyzed. Round goby’s nutrition spectrum were represented by 14 taxons of hydrobionts on the Belosaraiskа Bay. The highest value for nutrition supply of round goby had Malacostraca and Bivalvia classes. The rather clear tendency to increase of filling intestines indexes, and its highest value between from 11 a.m to 14 p.m were observed

Using VO Concept for Managing Dynamic Security Associations

This research paper presents results of the analysis how the Virtual Organisation (VO) concept can be used for managing dynamic security associations in collaborative applications and for complex resource provisioning. The paper provides an overview of the current practice in VO management at the organisational level and its support at the security middleware level in Grid based applications. The paper identifies open issues and basic requirements to the VO security functionality and services and suggests possible directions of further research and development, in particular, VO management concept, dynamic interdomain trust management for user-controlled applications, multi-domain policy decision and security context management. Proposed conceptual VO model addresses VO management issues and VO security services operation. The paper is based on experiences gained from the major Grid based and Grid oriented projects in collaborative applications and complex resource provisioning