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Sinterização de cerâmicas multiferróicas nanoestruturadas de Pb(Fe1/2Nb1/2)O3 e Pb(Fe2/3W1/3)O3 via Spark Plasma Sintering SPS
(Universidade Federal de São Carlos, 2013-02-25)
Considering the search for miniaturization of electronic devices, the development of new methods and techniques for the production and characterization of nanostructured materials is fundamental, beyond understanding of ...
Ferroelétricos relaxores canônicos: um estudo a partir do efeito eletro-óptico em função da temperatura
(Universidade Federal de São Carlos, 2013-11-28)
This study revisits the lanthanum-modified lead zirconate titanate ferroelectric relaxor system (PLZT) by investigating its electro-optical properties, particularly the variation of birefringence induced by electrical ...
Desenvolvimento de sistema para obtenção de filmes finos supercondutores de alta temperatura crítica (HTS) por deposição por laser pulsado (PLD)
(Universidade Federal de São Carlos, 2013-12-11)
In this PhD work, the building of a PLD (Pulse Laser Deposition) system was accomplished with resources provided by FAPESP / CEPID / CMDMC, for the purpose of depositing thin films using an 248 nm pulsed excimer laser as ...
Modelos dinâmicos de magnetização aplicados em compósitos magnetoelétricos
(Universidade Federal de São Carlos, 2014-04-01)
In this thesis we study the magnetic properties of the multiferroic composite (1-x)Pb(Mg1/3Nb2/3)-xPbTiO3/CoFe2O4 (PMN-PT/CFO) sintered by hot forging. Magnetization as a function of magnetic field, magnetoelectric effect ...
Comportamento multicrítico no modelo de Heisenberg frustrado: transições de fases clássica e quântica
(Universidade Federal de São Carlos, 2011-09-01)
In this work we study the critical behavior of systems described by the Anysotropic- Heisenberg model of spin 1/2 with competitive interactions (J1-J2 Model) on planes, and interplane nearest-neighbor interactions. We ...
Ansatz de Bethe algébrico com fronteiras triangulares
(Universidade Federal de São Carlos, 2014-05-26)
In this work we study vertex models with non-diagonal boundaries, characterized by reection matrices with an upper triangular form. By means of an extension of the algebraic Bethe ansatz, we construct generalized Bethe ...
Efeitos de spin em diodos de tunelamento ressonante tipo-p
(Universidade Federal de São Carlos, 2012-03-27)
In this work, we have investigated the spin effects in p-i-p GaAs/AlAs resonant tunneling diodes under magnetic field parallel to the tunnel current. The spin-dependent tunneling of carriers was studied by analyzing the ...
Simulações de líquidos super-resfriados via dinâmica molecular
(Universidade Federal de São Carlos, 2012-10-15)
This work presents the study of two models of glass-forming liquids using molecular dynamics simulations. The first model aims to analyze the effects on glassy dynamics which allow the enhancement of the glass formability ...
Propriedades de transporte de spins polarizados em heteroestruturas semicondutoras
(Universidade Federal de São Carlos, 2009-06-25)
In this work we used the technique of scattering matrix to calculate the transmissivity of polarized spins in a semiconductor symmetrical double-barrier heterostruture. The dynamics of carriers is described by effective ...
Estudo de primeiros princípios das propriedades eletrônicas de novos materiais derivados do grafeno : as nanofitas e nanofios
(Universidade Federal de São Carlos, 2012-09-05)
In this thesis, we study new materials derived from graphene, like nanowires and nanoribbons, with numerical calculations based on the density functional theory (DFT) and the non-equilibrium Green functions (NEGF). We will ...