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Now showing items 11-20 of 24
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) ...
Relaxação estrutural em ligas vítreas e parcialmente cristalizadas do sistema Cu-Zr-Al através da técnica de espectroscopia mecânica
(Universidade Federal de São Carlos, 2013-11-08)
In recent years the study of bulk metallic glasses (BMG) is being of great scientific and technological interest due to their unique properties (the lack of long range atomic order in the structure and compositional ...
Mecanismos de condução e relaxação elétrica em cerâmicas multiferróicas de Pb(Fe2/3W1/3)O3 e Pb(Fe1/2Nb1/2)O3
(Universidade Federal de São Carlos, 2013-12-19)
Multiferroic are materials which have at least two of the three ferroics orders: ferromagnetism, ferroelectricity and/or ferroelasticity. The coupling between these properties, make multiferroic materials of great technological ...
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 ...
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 ...
Efeito Aharonov-Bohm em partículas neutras
(Universidade Federal de São Carlos, 2011-03-14)
In classical Physics, the motion of an electrically charged particle is affected only by the presence of a magnetic field if the particle enters a region of space in which the field is present. Meanwhile, in quantum Physics, ...
Fabricação e caracterização de dispositivos baseados em nanofitas de Óxido de Estanho (SnO2)
(Universidade Federal de São Carlos, 2012-08-06)
The structural and transport features of tin oxide nanobelts synthesized by the vapor-solid method combined with the carbothermal reduction process were investigated in this work. The samples synthesized were characterized ...
Anelasticidade em titânio, tântalo e na liga Ti-40Ta
(Universidade Federal de São Carlos, 2014-07-24)
The growing demand for increasingly resistant and biocompatible with the human body implantable materials, has led to an increase in demand for new metallic biomaterials. Some materials, such as titanium and its alloys, ...
Ondas de spin em paredes de domínio unidimensionais em monocamadas magnéticas
(Universidade Federal de São Carlos, 2012-08-16)
Recent investigations on ferromagnetic monolayers predict the existence of spinwave modes without gap in the spectrum, even in the presence of anisotropy. These excitations propagate within the domain walls that exist in ...
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 ...