resumo
Polycrystalline compounds La0(.77-x)Mg(0.23)MnO(3) (0 <= x <= 0.2) were elaborated using the ceramic method. All the samples are indexed in the orthorhombic structure (Pnma space group). Zero-field-cooled (ZFC) and field-cooled (FC) magnetization measurements show that the samples undergo a paramagnetic-ferromagnetic phase transition and the transition temperature is found to increase from 140.82 K for x = 0.00 to 191.50 K, for x = 0.20. The compounds reveal a second-ordered magnetic phase transition around T c . Isothermal entropy change vertical bar - Delta S-M vertical bar was estimated using the Maxwell relation method. The relative cooling power also increases from 158.12 (J/Kg) for x = 0.00 to 175.94 (J/Kg) for x = 0.20, under a magnetic field of 5 T. The results suggest that materials could be useful for magnetic refrigeration.
palavras-chave
PHASE-TRANSITIONS; TRANSPORT; DIAGRAM
categoria
Engineering; Materials Science; Physics
autores
Selmi, R; Cherif, W; Sarabando, AR; Ferreira, NM; Ktari, L
nossos autores
Artur Ricardo Mesquita Sarabando
bolseiro de investigação
Nuno Miguel Freitas Ferreira
Bolseiro de pós-DoutoramentoGrupos
agradecimentos
This paper within the framework of collaboration is supported by the Tunisian Ministry of Higher Education and Scientific Research and the Portuguese Ministry of Science, Technology and Higher Education. The authors acknowledge the i3N (UID/CTM/50025/2020) and CICECO-Aveiro Institute of Materials (UID/CTM/50011/2020), financed by FCT/MEC and FEDER under the PT2020 Partnership Agreement. This work is also funded by national funds (OE), through FCT-Fundacao para a Ciencia e a Tecnologia, I.P., in the scope of the framework contract for eseen in the numbers 4, 5, and 6 of the article 23, of the Decree-Law 57/2016, of August 29, changed by Law 57/2017, of July 19.