Anisotropic Antiferromagnetic Systems
Mostrando 1-6 de 6 artigos, teses e dissertações.
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1. New functionals for the anisotropic Heisenberg model / Novos funcionais para o modelo de Heisenberg anisotrópico
The Heisenberg Model is generally recognized in the study of electromagnetism with origin in localized magnetic moments. Similar to the well known classical Ising model, it incorporates, however, quantum flutuations. We are interested in antiferromagnetic systems described by the Heisenberg Hamiltonian with exchange anisotropy and, eventually, non-null magne
Publicado em: 2008
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2. MagnetoresistÃncia em filmes e multicamadas magnÃticas
In this master dissertation, we have studied, at room temperature, magnetic and transport properties of metallic films and multilayer of different structures such as: single layer thin films, coupled trilayer, ferromagnetic/antiferromagnetic bilayer and spin valve. Phenomenological models, which take in account the most relevant magnetic free energy terms, w
Publicado em: 2005
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3. Applications of quantum field theory in condensed matter
We present a brief review of some applications of quantum field theory in condensed matter systems. These include isotropic and anisotropic antiferromagnetic chains, strongly correlated organic conductors, such as the Bechgaard salts, carbon nanotubes and high-Tc superconductors. The review is by no means exhaustive and points to a vast range of new interest
Brazilian Journal of Physics. Publicado em: 2004-12
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4. Estudo sistematico das propriedades termodinâmicas e criticalidade de filmes finos e super-redes magnéticas.
In this work we will study through the differential operator technique the surface effect in anisotropic spin quantum Heisenberg model, through theory of effective field (EFT), of a two-spins cluster, in case of simple cubic lattice. Those systems are characterized by the existence of the surfaces, thin films and superlattice, or the bulk. Therefore, the exc
Publicado em: 2004
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5. Estudo de ordenamento multipolar eletrico de holmio por difração de raios-X
Multipolar ordering in metallic holmium 4f shell was extensively studied for the first time, by resonant and non resonant X-ray scattering at the helical antiferromagnetic and conical ferromagnetic phases. The strong spin-orbit coupling drives the multipolar order as it was experimentally confirmed through the temperature dependence of the ordering wave-vect
Publicado em: 2003
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6. Determination of the boundaries of the anisotropic antiferromagnetic systems phase at low temperatures / Determinação das fronteiras de fase de sistemas antiferromagnéticos anisotrópicos a baixas temperaturas
A combinação das funções de Green para operadores de criação e destruição de bosons com as transformações de Holstein e Primakoff é utilizada na análise de sistemas antiferromagnéticos, isolantes e anisotrópicos, na região de baixas temperaturas. Os limites de estabilidade das fases antiferromagnética e \"spin-flop\", assim como a transição
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 12/11/1980