Magnetocaloric effect in GdGeSi compounds measured by the acoustic detection technique: Influence of composition and sample treatment

Magnetocaloric effect in GdGeSi compounds measured by the acoustic detection technique: Influence of composition and sample treatment

Autor Guimaraes, A. O. Google Scholar
Soffner, M. E. Google Scholar
Mansanares, A. M. Google Scholar
Coelho, A. A. Google Scholar
Carvalho, A. Magnus G. Google Scholar
Pires, M. J. M. Google Scholar
Gama, S. Autor UNIFESP Google Scholar
Silva, E. C. da Google Scholar
Instituição Univ Estadual Norte Fluminense
Universidade Estadual de Campinas (UNICAMP)
Inst Nacl Metrol Normalizacao & Qualidade Ind INM
Universidade Federal de São Paulo (UNIFESP)
Resumo In this paper we explore the acoustic detection method applied to the investigation of the magnetocaloric effect in Gd and Gd(5)(Ge(1-x)Si(x))(4) compounds, in the temperature range from 230 to 360 K and for magnetic fields up to 20 kOe. Measurements were performed in as-cast materials, both for powder and pellet samples, and in tree samples with compositions around Gd(5)Ge(2)Si(2) that underwent different thermal treatments. Small differences were observed when comparing powder and pellet samples of Gd and Gd(5)(Ge(1-x)Si(x))(4) compounds with 0.500<x <= 1.00. for the alloys with composition around Gd(5)Ge(2)Si(2), which exhibit giant magnetostriction and coexistence of distinct phases, expressive changes were observed when comparing powder and pellet samples. Based on these cases, it is easy to see that the acoustic method can distinguish a second-order phase transition from a first-order magnetic-crystallographic one, and that it presents good sensitivity to detect spurious material phase in small quantities. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3357375]
Idioma Inglês
Financiador Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
FAEPEX-Unicamp
Data de publicação 2010-04-01
Publicado em Journal of Applied Physics. Melville: Amer Inst Physics, v. 107, n. 7, 6 p., 2010.
ISSN 0021-8979 (Sherpa/Romeo, fator de impacto)
Publicador Amer Inst Physics
Extensão 6
Fonte http://dx.doi.org/10.1063/1.3357375
Direito de acesso Acesso restrito
Tipo Artigo
Web of Science WOS:000276795400038
Endereço permanente http://repositorio.unifesp.br/handle/11600/32440

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