Origem dos momentos magnéticos localizados em ligas de cromo com metais de transição por oscilações de Friedel

• Ano de defesa: 2006
• Autor(a) principal: Souza, Paulo Eduardo Narcizo de
• Orientador(a): Oliveira, Adilson Jesus Aparecido de
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de São Carlos
• Programa de Pós-Graduação: Programa de Pós-Graduação em Física - PPGF
• País: BR
• Palavras-chave em Português: Magnetismo itinerante; Antiferromagnetismo; Ondas de densidade de Spin; Cromo; Oscilações de Friedel; Ondas de densidade de carga
• Área do conhecimento CNPq: CIENCIAS EXATAS E DA TERRA::FISICA
• Link de acesso: https://repositorio.ufscar.br/handle/20.500.14289/4905

The fundamental magnetic properties of chromium and its alloys Cr(1¡x)Nb(x) and Cr(1¡x)V(x), were investigated with the aim to achieve a better comprehension about the nature of the spin density waves. Was dened the edge between the AF1 and AF2 phases on the Cr(1¡x)Nb(x) alloys as function of niobium concentration. Using x-rays di®raction techniques was studied de formation of antiferromagnetic domains in the surfaces with [001] direction of chromium samples. As observed, cooling the sample under applied magneticeld do not create new magnetic domains, actuating only on its reorien- tation. The magnetic history of sample does not in°uence the surface magnetic domains formation, been an exclusive property of the sample surface crystalographic orientation. Was observed the formation of localized magnetic moment on paramagnetic phase of Cr(1¡x)Nb(x) alloys. This phenomenon early studied in Cr(1¡x)V(x) alloys, shown important qualitative di®erences which are explained on Friedel oscillations picture generated by impurity atoms. Was realized x-rays di®raction experiments which provided evidences of the existence of Friedel oscillations in Cr(1¡x)V(x) alloys.