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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 ...
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 ...
Caracterização ótica não-linear em cerâmicas ferroelétricas transparentes (CFT s) de PLZT: TR (TR = nd,Ho, Er, Tm e Yb)
(Universidade Federal de São Carlos, 2009-10-02)
Lead titanate zirconate modified with lanthanum, or PLZT, is one the most ferroelectric compounds utilized in electronic devices, due to its versatility and low production costs in comparison with single-crystalline ...
Modelo do potencial ótico complexo para estudo de espalhamento de elétrons por moléculas e radicais livres
(Universidade Federal de São Carlos, 2008-04-11)
In this work, we seek a better understanding of the role of the absorption potential involved in the dynamics of electron-atom (-molecule) interactions, in arder to develop a po¬tential model that better represents the ...
Estudo por espectroscopia Raman de efeitos de localização das excitações elementares em superredes e em ligas dopadas.
(Universidade Federal de São Carlos, 2005-03-22)
In the present work, the localization properties of the single-particle and collective excitations subjected to a random potential in the AlGaAsSi alloys and in the intentionally disordered GaAs/AlGaAs:Si superlattices (SL ...
Obtenção e caracterização de perovskitas supercondutoras monocristalinas do tipo YxPr1-xBa2Cu3O7-δ dopadas por Fe, Ni, Ga e Zn
(Universidade Federal de São Carlos, 2009-04-30)
The Praseodymium is known to have a singular behavior in the family of cuprate superconductors of high critical temperature of the type RE-123. When these cuprates are doped with Praseodymium apparently critical temperature ...
Estudo de nanopartículas para preparação de compósitos com acoplamento magnetoelétrico
(Universidade Federal de São Carlos, 2009-09-03)
In recent years the necessity of new devices, in the electroelectronic industry, has lead to an increasing interest in materials called magnetoelectric (ME) or multiferroic (MF). Multiferroic is the term used to classify ...
Síntese e caracterização de nanopartículas de óxido de ferro e de grafite magnética fluida (GMF)
(Universidade Federal de São Carlos, 2008-09-05)
In this work were studied the physical properties of magnetic nanoparticles, based on iron oxide, and magnetic graphite fluid particles. The work was developed in three steps: 1) synthesis of the magnetic nanoparticles of ...
Construção e caracterização do campo acústico de transdutores ultra-sônico piezoelétrico de polarização variável
(Universidade Federal de São Carlos, 2008-10-23)
This work was motivated on the great technological and commercial interest of ultrasonic transducer, capable to generate diffraction controlled ultrasonic beams in the
frequency range of kHz up to MHz. As a solution, in ...
Diagrama de fases magnéticas e transição de fase quântica em ligas de Cr-Ti
(Universidade Federal de São Carlos, 2009-03-30)
In this work we present the results of characterization of Cr-Ti alloys with small quantities of Ti. The samples were prepared in a melting arc furnace, using hight purity Cr and Ti. The magnetic phase diagram was determined ...