3,930 research outputs found
Role of hexagonal boron nitride in protecting ferromagnetic nanostructures from oxidation
Ferromagnetic contacts are widely used to inject spin polarized currents into
non-magnetic materials such as semiconductors or 2-dimensional materials like
graphene. In these systems, oxidation of the ferromagnetic materials poses an
intrinsic limitation on device performance. Here we investigate the role of
ex-situ transferred chemical vapour deposited hexagonal boron nitride (hBN) as
an oxidation barrier for nanostructured cobalt and permalloy electrodes. The
chemical state of the ferromagnets was investigated using X-ray photoemission
electron microscopy owing to its high sensitivity and lateral resolution. We
have compared the oxide thickness formed on ferromagnetic nanostructures
covered by hBN to uncovered reference structures. Our results show that hBN
reduces the oxidation rate of ferromagnetic nanostructures suggesting that it
could be used as an ultra-thin protection layer in future spintronic devices.Comment: 7 pages, 6 figure
Potential of a New Technique for Remote Sensing of Hydrocarbon Accumulations and Blind Uranium Deposits: Buried Lif Thermoluminescence Dosimeters
Buried thermoluminescence dosimeters may be useful in remote sensing of petroleum and natural gas accumulations and blind uranium deposits. They act as integrating detectors that smooth out the effects of environmental variations that affect other measuring systems and result in irregularities and poor repeatability in measurements made during gas and radiometric surveys
Pesquisa Ă© peça-chave na melhoria da segurança dos alimentos de ordem avĂcola.
Projeto: 11.11.11.111
Magnetic anisotropy modulation of magnetite in Fe3O4/BaTiO3(100) epitaxial structures
Temperature dependent magnetometry and transport measurements on epitaxial
Fe3O4 films grown on BaTiO3(100) single crystals by molecular beam epitaxy show
a series of discontinuities, that are due to changes in the magnetic anisotropy
induced by strain in the different crystal phases of BaTiO3. The magnetite film
is under tensile strain at room temperature, which is ascribed to the lattice
expansion of BaTiO3 at the cubic to tetragonal transition, indicating that the
magnetite film is relaxed at the growth temperature. From the magnetization
versus temperature curves, the variation in the magnetic anisotropy is
determined and compared with the magnetoelastic anisotropies. These results
demonstrate the possibility of using the piezoelectric response of BaTiO3 to
modulate the magnetic anisotropy of magnetite films.Comment: 4 pages, 4 figure
An application of semi-infinite programming to air pollution control
Environment issues are more then ever important in a modern society.
Complying with stricter legal thresholds on pollution emissions raises an important economic issue. This talk presents some ideas in the use of optimization tools to help in the planning and control of non mobile pollution sources.
We assume a Gaussian plume model where a plume rise and weather stabilities classes are considered.
Three main semi-infinite programming formulations are described and numerical results are shown
Determinação eletroanalĂtica do pesticida paration metĂlico em eletrodo de carbono vĂtreo.
bitstream/CNPDIA-2009-09/11854/1/DOC26_2006.pd
- …