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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 ...
Estudo sistemático das propriedades estruturais e magnéticas de amostras policristalinas do sistema PrxY1-xBa2Cu3O7-d
(Universidade Federal de São Carlos, 2008-08-10)
One of the most studied high TC superconductor is the YBa2Cu3O7 (Y-123) as well as the different substitutions on the Y site for different rare earth elements. Generally, this does not show important effects on the magnetic ...
Dielectric and elastic response of perovskites: modelling and simulation
(Universidade Federal de São Carlos, 2013-09-09)
Nesta tese é estudada a resposta elástica e elétrica das perovskitas. As perovskitas são amplamente utilizadas em aplicações técnicas, sendo fundamental na eletrônica e no campo relativamente novo da nanoeletrônica. Elas ...
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 ...
Estrutura de platô na magnetização em modelos de spins frustrados
(Universidade Federal de São Carlos, 2012-10-26)
This thesis study the phase transition, forms classical and quantum models of spin frustration. The Heisenberg model of spin 1/2 with exchange anisotropy with competitive interactions between first (J1) and second (J2) ...
Processamento e propriedades do sistema ferroelétrico (Li,K,Na)(Nb,Ta)O3 dopado com CuO
(Universidade Federal de São Carlos, 2015-03-09)
The search for new lead-free piezoelectric materials has been a major goal of many scientists in recent years. The main cause is the replacement of widely used lead zirconate titanate (PZT) based ceramics due to the highly ...
Efeito da modulação da topologia do confinamento em sistemas quase zero-dimensionais induzida por campo elétrico
(Universidade Federal de São Carlos, 2015-04-01)
Quantum dots grown by epitaxial techniques for optical and transport studies are usually capped by a layer of the same material on which the QDs were grown. Recently, several studies have shown how the growth parameters ...
Optical and transport properties of p-i-n GaAs/AlAs resonant tunneling diode
(Universidade Federal de São Carlos, 2014-05-26)
In this thesis, we have investigated the optical and transport properties of a p-i-n GaAs-AlAs resonant tunneling diode (RTD). The possibility of controlling and significantly varying the density of carriers accumulated ...
Caracterização magnética de compósitos multiferróicos particulados Pb(Zr0,52Ti0,48)O4/CoFe2O4
(Universidade Federal de São Carlos, 2014-08-26)
This work was studied the magnetic and electrical properties of particulate multiferroic composite Pb (Zr0,52Ti0,48) O4 / CoFe2O4 (PZT / CFO) (0-3 type) prepared by the polymeric method of Pechini and sintered by ultra-rapid ...
Efeitos eletrônicos, elásticos e estruturais em sistemas semicondutores nanoscópicos
(Universidade Federal de São Carlos, 2012-02-16)
The present work aims the study of electronic, elastic and structural properties of a whole class of nanoscopic semiconductors systems, which include quasi-two-dimensional, one-dimensional and zero-dimensional confined ...