Artículos de revistas
Specific heat of Gd4Co3
Registro en:
Journal Of Physics-condensed Matter. Iop Publishing Ltd, v. 22, n. 13, 2010.
0953-8984
WOS:000275683000018
10.1088/0953-8984/22/13/136002
Autor
Seixas, TM
da Silva, MAS
de Lima, OF
Lopez, J
Braun, HF
Eska, G
Institución
Resumen
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) 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. 22 13 FCT project [POCTI/2000/CTM/36224-Sapiens] TMR program [ERBFMGECT-950072] Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) FCT project [POCTI/2000/CTM/36224-Sapiens] TMR program [ERBFMGECT-950072]