Charge-ordering contribution to the magnetic entropy change of (Pr, Ca)MnO3 manganites

• Tipo: Artigo em Revista Científica Internacional
• Data: 2005

Autores

Reis, Mário Souza (Autor) Outra; Gomes, Angelo M S (Autor) Outra; Araújo, João Pedro (Autor) FCUP; Amaral, J. S. (Autor) Outra; Tavares, Pedro B. (Autor) Outra; Oliveira, Ivan S. (Autor) Outra; Amaral, V. S. (Autor) Outra

Revista

Título: Journal of Magnetism and Magnetic Materials

Vol. 290

Páginas: 697-699

ISSN: 0304-8853

Editora: Elsevier

Indexação

ISI Web of Knowledge - 8 Citações

Scopus - 8 Citações

Outras Informações

ID Authenticus: P-000-428

DOI: 10.1016/j.jmmm.2004.11.340

Abstract (EN): In the present work, we analyze the influence of the charge-ordering on the magnetic entropy change of Pr1-xCaxMnO3 manganites (0.20 < x < 0.95). The samples with x < 0.30 and x > 0.90 present the usual ferromagnetic and antiferromagnetic behavior, peaking at the Curie and Neel temperature, respectively. In contrast, for the samples with charge-ordering (0.30 < x < 0.90), a much smaller positive peak on the magnetic entropy change was observed around the charge-ordering temperature T-CO. This effect is associated to a negative contribution from the spin ordering Delta S-spin which is superimposed to a positive contribution due the charge-ordering Delta S-CO. We could also appraise Delta S-CO(max) as a function of Ca content (0.30 < x < 0.90), under 4 T of magnetic field change. Delta S-CO(max) vanishes for the limits x similar to 0.30 and similar to 0.90, and presents a deep minimum around x similar to 0.50, with two maxima at x similar to 0.35 and 0.65.

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 3