Título: | ANTIFERROMAGNETISM AND QUANTUM CRITICAL POINT IN CECOGE(2,1)SI(0,9) COMPOUND UNDER PRESSURE | ||||||||||||||||||||||||||||||||||||||||
Autor: |
MARIELLA ALZAMORA CAMARENA |
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Colaborador(es): |
HORTENCIO ALVES BORGES - Orientador MAGDA BITTENCOURT FONTES - Coorientador |
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Catalogação: | 01/ABR/2008 | Língua(s): | PORTUGUESE - BRAZIL |
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Tipo: | TEXT | Subtipo: | THESIS | ||||||||||||||||||||||||||||||||||||||
Notas: |
[pt] Todos os dados constantes dos documentos são de inteira responsabilidade de seus autores. Os dados utilizados nas descrições dos documentos estão em conformidade com os sistemas da administração da PUC-Rio. [en] All data contained in the documents are the sole responsibility of the authors. The data used in the descriptions of the documents are in conformity with the systems of the administration of PUC-Rio. |
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Referência(s): |
[pt] https://www.maxwell.vrac.puc-rio.br/projetosEspeciais/ETDs/consultas/conteudo.php?strSecao=resultado&nrSeq=11502&idi=1 [en] https://www.maxwell.vrac.puc-rio.br/projetosEspeciais/ETDs/consultas/conteudo.php?strSecao=resultado&nrSeq=11502&idi=2 |
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DOI: | https://doi.org/10.17771/PUCRio.acad.11502 | ||||||||||||||||||||||||||||||||||||||||
Resumo: | |||||||||||||||||||||||||||||||||||||||||
Studies on the pseudo ternary system CeCoGeSix (where 0 = < x = < ) have shown that the system evolves continuously
from a Kondo lattice antiferromagnetic state ( CeCoGe(3)
with ) towards a mixed valent compound ( CeCoSi(3)with Tw
~230k ). The system displays a non-Fermi-liquid-type
behavior (NFL) in the vicinity of the quantum critical
point (QCP) at the critical concentration . Isoelectronic
substitution of atoms for does not enhance the degree of
magnetic disorder, rendering it ideal for the study of the
Kondo lattice¡ s interaction constants intrinsic effects.
We
have studied this system in polycrystalline samples at
concentrations close to the critical one through AC
electrical resistivity under pressure (x= 0,9) and magnetic
field (x=1) measurements. Our results show that the long
range magnetic order present in the CeCoGe(2,1)Si(0,9)
sample is suppressed as pressure is increased, and that for
the critical pressure PC (aprox. 6,2 kbar), TN (aprox.
zero) . For temperatures below TN, the resisitivity data
are well described considering conduction electron
scattering by anisotropic antiferromagnetic magnons. Above
PC we observe the Fermi liquid behavior. At the critical
region, a NFL state with exponents close to 1 was found.
The analysis of the behavior of the critical line in the
neighborhood of the QCP indicates that the relevant
magnetic fluctuations are typically two-dimensional. On the
other hand, the CeCoGe(2)Si compound displays short range
order (TN ~ 2k). The ordering temperature is reduced under
an increase of an applied magnetic field, and for magnetic
fields above 3 T a Fermi liquid behavior arises.
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