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Now showing items 11-20 of 81
Transição de fase quântica e modelos de spins frustrados
(Universidade Federal de São Carlos, 2007-03-15)
In this thesis, we will study the quantum phase transition of frustrated quantum spin
models: (i) van Hemmen model ( S = 1) with transverse and anisotropic biaxial field (ii)
Heisenberg model (S = 1/2 ) with competitive ...
Estudos sobre a inclusão da correlação eletrônica do alvo no espalhamento elástico elétron-molécula e sobre a ionização molecular por impacto de elétrons
(Universidade Federal de São Carlos, 2003-12-10)
In this work we present two contributions to the electron-molecule collision theory. Firstly, we present a new theoretical procedure to introduce the target electronic correlation in the elastic electron-molecule scattering. ...
Dispersão dielétrica em materiais ferroelétricos.
(Universidade Federal de São Carlos, 2004-12-13)
In the last decades, the high frequency dielectric response has been one of
the most studied issues in the ferroelectricity area. The main dielectric
characteristic is the strong dependence of the dielectric parameters ...
Magnetorresistência túnel ressonante e acoplamento magnético em heteroestruturas epitaxiais.
(Universidade Federal de São Carlos, 2004-10-29)
In the context of spin electronics, this doctorate thesis presents an
experimental study of spin polarized transport in epitaxial heterostructures as planar
magnetic tunnel junctions formed by semiconductors and metallic ...
Investigação por espectroscopia Mössbauer das fases formadas e sua influência na resistência à corrosão do aço inoxidável austenítico AISI 316L nitretado
(Universidade Federal de São Carlos, 2009-03-10)
The plasma nitriding is a technique that improves mechanical and tribological properties of metallic materials as hardness and wear. It improves also the corrosion resistance, because the nitrated layer is formed by phases ...
Espectroscopia mecânica em tântalo
(Universidade Federal de São Carlos, 2007-03-15)
The mechanical spectroscopy technique applied to diffusion studies in body-centered cubic (BCC) metals, such as tantalum. Transition metals, as the tantalum, that has a crystalline structure (BCC), can dissolve large amounts ...
Simulações por dinâmica molecular de compostos do tipo ABO3 (SrTiO3 e CaTiO3)
(Universidade Federal de São Carlos, 2009-02-26)
Using the classical molecular dynamics simulations, Perovskites systems composed by oxides (ABO3), in particular SrTiO3 and CaTiO3, were performed. The titanates are easily prepared as polycrystalline ceramics; chemically ...
Caracterização magnética de filmes de cromo e cromocobalto preparados por eletrodeposição
(Universidade Federal de São Carlos, 2008-12-11)
Magnetic properties of electrodeposited of chromium and chromium-cobalt thin films on cooper substrate were investigated. The samples were prepared without introduction of additives. This procedure following to samples ...
Equação mestra não-linear aplicada ao estudo de bioestabilidade óptica.
(Universidade Federal de São Carlos, 2004-08-12)
In this dissertation, we present a generalized master equation for a system of N two-
level atoms pumped by a classical field, interacting with a reservoir. The kinds of reservoirs
are assumed: (a) thermal, (b) squeezed ...
O estudo do limite de transporte interfilamentar de supercorrentes em amostras supercondutoras de BSCCO.
(Universidade Federal de São Carlos, 2006-03-15)
In this work, we have studied the behavior of the line H*(T) in filamentary samples of BSCCO, which were grown by the LFZ technique, Laser Floating Zone. Previously studied in other specimens prepared by specific routes ...