Superlattice
Mostrando 1-12 de 33 artigos, teses e dissertações.
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1. Structural, Atomic and Electrostatic Force Microscopy Analyses on YBCO/PBCO/LCMO Superlattices
In order to study the influence of the insulator layer thickness in heterojunctions, (YBa2Cu3O7-δ[20nm]/ PrBa2Cu3Oy/La1/3Ca2/3MnO3[20nm])x20 superlattices were prepared by pulsed laser deposition using three PrBa2Cu3Oy layer thicknesses and two different sequences of deposition. Sample characterization showed primitive orthorhombic crystalline arrangement f
Mat. Res.. Publicado em: 03/04/2017
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2. Propriedades físicas do SnO2: defeitos, impurezas, ligas e superredes. / Physical properties of SnO2: defects, impurities, alloys and superlattices.
O dioxido de estanho na estrutura rutila (SnO2) é um semicondutor de gap largo e faz parte da classe dos óxidos condutores transparentes (TCO). Possui gap direto de 3,6 eV e condutividade do tipo n, mesmo quando não dopado intencionalmente. Estudos teóricos e experimentais atribuem este comportamento à presença de defeitos intrínsecos. Por outro lado,
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 19/08/2011
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3. Ferromagnetic Resonance in Super-Lattice Nife/RU / Ressonância Ferromagnética em Super-Redes NiFe/Ru
The Ferromagnetic Resonance (FMR) technique was used to study the magnetic anisotropy of NiFe/Ru multilayers. The FMR spectra and absorption fields of multilayers with Ru layers thickness bellow 20 Å are the same as that of single monolayer films. Evidence of the coupling between the magnetic layers also is given by the fact that for the sample with Ru thic
Publicado em: 2009
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4. Ressonância Ferromagnética em Super-Redes NiFe/Ru / Ferromagnetic Resonance in Super-Lattice Nife/RU
A técnica de Ressonância Ferromágnética (RFM) foi aplicada para estudar a anisotropia magnética de multicamadas NiFe/Ru. Os espectros de RFM e os campos de absorção das multicamadas com espessura da camada de Ru abaixo de 20 Å são os mesmos daqueles obtidos para um filme monocamada. Uma evidência do acoplamento entre as camadas magnéticas destas a
Publicado em: 2009
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5. Ressonância Ferromagnética em Super-Redes NiFe/Ru / Ferromagnetic Resonance in Super-Lattice Nife/RU
A técnica de Ressonância Ferromágnética (RFM) foi aplicada para estudar a anisotropia magnética de multicamadas NiFe/Ru. Os espectros de RFM e os campos de absorção das multicamadas com espessura da camada de Ru abaixo de 20 Å são os mesmos daqueles obtidos para um filme monocamada. Uma evidência do acoplamento entre as camadas magnéticas destas a
Publicado em: 2009
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6. Espalhamento Raman de Sistemas a Base de GaN Dopados
In this work we present calculations of eletronic Raman cross-sections of doped GaN based system via charge - density mechanism. The studied structures were -doped superlattices and uniform doped GaN systems. In the case of periodically doped superlattice the eletronic structure was obtained using Density Funcional Theory in the local density approximation.
Publicado em: 2007
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7. Polaritons em materiais magnéticos nanoestruturados
Neste trabalho apresentamos um estudo teórico sobre as propriedades dos polaritons magnéticos em super-redes organizadas em padrões periódico e quasiperiódico. Na super-rede periódica, objetivando descrever o comportamento destes modos, tanto no volume quanto na superfície, foi utilizada a teoria do meio efetivo, que facilita enormemente a álgebra en
Publicado em: 2007
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8. Estruturas de bandas e propriedades de simetria dos modos eletromagnéticos em um cristal fotônico unidimensional
We perform in this work, through the techniques of transfer matrix, an analytical study of the photonic band structure and the density of states of a one dimensional photonic crystal consisting of a super-lattice composed by two alternating layers of air and GaAs of thicknesses a and the b, respectively. We find photonic band gaps, as expected, and also null
Publicado em: 2007
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9. The effective charge velocity of spin-¹/2 superlattices
We calculate the spin gap of homogeneous and inhomogeneous spin chains, using the White's density matrix renormalization group technique. We found that the spin gap is related to the ration between the spin velocity and the correlation exponent. We consider a spin superlattice, which is composed of a repeated pattern of two spin-¹/2 XXZ chains with differen
Brazilian Journal of Physics. Publicado em: 2006-09
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10. Luminescence from miniband states in heavily doped superlattices
We have studied doped superlattices of GaAs/AlGaAs composition. When the doping atoms are introduced into the barriers surrounding the superlattice, as well as to the inner ones, but with half of the concentration, the photoluminescence due to interband transitions from extended superlattice states is detected. This is demonstrated by a study of the sample´
Brazilian Journal of Physics. Publicado em: 2004-06
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11. Monte Carlo studies of miniband conduction in extreme type-II superlattices
Miniband charge transport was investigated by Monte Carlo simulations of electronic motion in short period superlattices of type-II energy band alignment (InAs/GaSb composition). The strong decrease of the miniband energy width when the electronic in-plane energy increases, characteristic of type-II superlattices, leads to a conductivity that is very sensiti
Brazilian Journal of Physics. Publicado em: 2004-06
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12. Hall effect in InAs/GaAs superlattices with quantum dots: identifying the presence of deep level defects
We have carried out van der Pauw resistivity and Hall effect measurements on a series of Molecular Beam Epitaxy InAs/GaAs superlattice samples containing InAs quantum dots. Three growth parameters were varied, the InAs coverage, the number of repetitions of the InAs/GaAs layers, and the GaAs spacer thickness. The results can be grouped in two sets, those sam
Brazilian Journal of Physics. Publicado em: 2004-06