Specific heat of Gd4Co3

• Tipo: Artigo em Revista Científica Internacional
• Data: 2010

Autores

T.M. Seixas (Autor) FCUP; M.A. Salgueiro da Silva (Autor) FCUP; O.F. de Lima (Autor) Outra; J. Lopez (Autor) Outra; H.F. Braun (Autor) Outra; G. Eska (Autor) Outra

Revista

Título: Journal of Physics Condensed Matter

Vol. 22 Nº 13

Página Inicial: 136002

ISSN: 0953-8984

Editora: Institute of Physics Publishing

Indexação

ISI Web of Knowledge - 13 Citações

ISI Web of Science

Scopus - 13 Citações

Classificação Científica

FOS: Ciências exactas e naturais > Física

Outras Informações

ID Authenticus: P-003-7HV

Abstract (EN): The specific heat (C(T)) of Gd4Co3 was measured in the temperature range 2-300 K and its magnetic contribution (C-m(T)) was determined using a new method that fits the electronic specific heat coefficient (gamma) and the Debye temperature (theta(D)) by constraining the resulting magnetic entropy (S-m(T)) to saturate at temperatures far above the Curie temperature (T-C). C-m(T) exhibits a low-temperature bump originating from thermal excitation of gapped spin waves, which is responsible for pronounced peaks, at approximate to 35 K, in both C-m/T and the temperature derivative of the magnetic contribution to electrical resistivity (d rho(m)/dT). Apart from in the vicinity of T-C, an excellent global correlation was found between C-m/T and d rho(m)/dT. Our results provide strong support for the consistency of the new method proposed for the determination of C-m(T) and rule out any major role of short-range order on Gd moments or d-electron spin fluctuation effects in the paramagnetic phase. A comparative analysis with other methods used in similar compounds points to the need for a better evaluation of C-m(T) in such compounds, especially in the magnetically ordered phase, where a deficient evaluation of C-m/T has a larger impact on the S-m(T) curve.

Idioma: Inglês

Tipo (Avaliação Docente): Científica