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Modelagem computacional de estruturas de poços quânticos semicondutores para dispositivos optoeletrônicos e spintrônicos
(Universidade Federal de São Carlos, 2014-01-29)
In the present thesis, we realize a computational modeling of semiconductor structures based on multiple quantum wells with filter barriers and on quantum wells with semiconductor diluted magnetic layers. We numerically ...
Contribuições ao estudo do transporte eletrônico em nanofios semicondutores : localização e estados de interface
(Universidade Federal de São Carlos, 2013-04-11)
In this work, we studied the influence of surface charges on the properties (especially electronic transport) of semiconductor nanowires and nanobelts via computer simulations and also they were compared to experimental ...
Magnetismo de nanofios de cobalto e níquel fabricados por eletrodeposição em alumina anódica porosa
(Universidade Federal de São Carlos, 2015-03-04)
In this thesis were investigated the magnetic properties of magnetic nanowire arrays of Co and Ni electrodeposited in porous anodic alumina templates. The electrochemical method was employed in the manufacturing steps of ...
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 ...
Modelos de spins geometricamente frustrados: transição de fase e estruturas de platores
(Universidade Federal de São Carlos, 2013-04-08)
This thesis presents a study of the magnetization plateau and the phenomenon of geometrical frustration in spin systems applied to lattices with triangular structure, as well as the results achieved by applying the ...
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 ...
Flux avalanches in patterned superconducting thin films: ac susceptibility, morphology and related studies
(Universidade Federal de São Carlos, 2013-04-12)
Avalanches are sudden dramatic phenomena that occur in nature. The technique of magneto-optical imaging (MOI) has allowed us to observe abrupt flux entrances in superconductors, the so-called ux avalanches, due to ...
Visualização de estrutura de domínios em cerâmicas e nanoestruturas ferroelétricas via microscopia de piezoresposta
(Universidade Federal de São Carlos, 2013-02-27)
In this work, the domain structure of a transparent ferroelectric ceramic of (Pb0,79La0,21)TiO3 (PLT 21) was investigated in detail by piezoresponse force microscopu (PFM) and a protocol of measurements and analysis of the ...
Influência da freqüência da corrente alternada da nitretação a plasma nas propriedades superficiais do aço inoxidável ASTM F138
(Universidade Federal de São Carlos, 2013-06-10)
Plasma nitriding is a technique which is used in surface treatments of stainless steel, in order to improve some properties like hardness, wear and corrosion resistance. The nitrided layer consists of some iron nitrides: ...