resumo
In this paper we explore the magnetocaloric effect (MCE) of chromium-doped elpasolite Cs2NaAl1-x,CrxF6 (x = 0.01 and 0.62) single crystals. Magnetization and heat capacity data show the magnetocaloric potentials to be comparable to those of garnets, perovskites, and other fluorides, producing magnetic entropy changes of 0.5 J/kg K (x = 0.01) and 11 J/kg K (x = 0.62), and corresponding adiabatic temperature changes of 4 and 8 K, respectively. These values are for a magnetic field change of 50 kOe at a temperature around 3 K. A clear Schottky anomaly below 10 K, which becomes more apparent when an external magnetic field is applied, was observed and related to the splitting of the Cr3+ energy levels. These results hint at a new family of materials with potential wide use in cryorefrigeration.
palavras-chave
CS2NAALF6 SINGLE-CRYSTALS; MAGNETIC REFRIGERATION; CR3+ IONS; CS2NAGAF6 CRYSTALS; OPTICAL-PROPERTIES; SPECTROSCOPY; ELPASOLITES; RESONANCE; FIELD
categoria
Physics
autores
Pedro, SS; Tedesco, JCG; Yokaichiya, F; Brandao, P; Gomes, AM; Landsgesell, S; Pires, MJM; Sosman, LP; Mansanares, AM; Reis, MS; Bordallo, HN
nossos autores
Paula Cristina Ferreira da Silva Brandão
Investigador Auxiliaragradecimentos
We thank Pedro von Ranke (UERJ, Brazil) and Walter Kalceff (UTS, Australia) for fruitful discussions. J.C.G.T.'s participation in this work was financed by the Science without Borders Program. Access to CICECO/Chemistry Department (Aveiro, Portugal), GPMR-UNICAMP (Campinas, Brazil), LMBT- UEE (Niteroi, Brazil), LBT-UFRJ (Rio de Janeiro, Brazil), BERII facilities, and LaMMB MagLab (Berlin, Germany) are gratefully acknowledged by all authors. Financial support was provided by Proppi/UFF, FAPERJ, FAPESP, CAPES, CNPq, and FINEP.