Magnetocaloric Effect in Nanostructured Pr2Fe17 and Nd2Fe17 Synthesized by High-Energy Ball-Milling

P. Alvareza, J. Sánchez-Marcosb, J.L. Sanchez Llamazaresc, V. Francod, M. Reifferse, J.A. Blancoa and P. Gorriaa aDepartamento de Física, Universidad de Oviedo, Calvo Sotelo, s/n, 33007 Oviedo, Spain bInstituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, 28049 Madrid, Spain cInstituto Potosino de Investigación Científica y Tecnológica, Camino a la Presa San José, 2055, Col. Lomas 4a , San Luis Potosí, S.L.P. 78216, Mexico dDepartamento de Física de la Materia Condensada, ICMSE-CSIC, Universidad de Sevilla, P.O. Box 1065, 41080 Sevilla, Spain eInstitute of Experimental Physics, Watsonova 47, SK-04001 Košice, Slovakia

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Nanocrystalline Pr2Fe17 and Nd2Fe17 powders with rhombohedral Th2Zn17-type crystal structure and average particle sizes around 20 nm have been obtained by high-energy ball milling. While the bulk alloys show a well-defined and sharp drop in the low-field magnetization curve at the Curie temperature, TC = 285 K (Pr) and 335 K (Nd), the ball-milled samples exhibit a substantial broadening of the ferro-to-paramagnetic transition due to a considerable augmentation of the disordered inter-grain boundaries. The latter results in an increase of more than 25% in the values of the full width at half maximum of the temperature dependence of the magnetic entropy change maintaining almost unchanged the relative cooling power.

DOI: 10.12693/APhysPolA.118.867 PACS numbers: 61.05.cp, 75.50.Tt, 75.30.Kz