Structural and Magnetocaloric Study of the LaFe11.0Co0.8(Si0.4Al0.6)1.2 Alloy

P. Gębaraa, P. Pawlika, I. Škorvánekb, J. Marcinb and J.J. Wysłockia aInstitute of Physics, Częstochowa University of Technology, al. Armii Krajowej 19, 42-200 Częstochowa, Poland bInstitute of Experimental Physics SAS, Watsonova 47, 040 01 Košice, Slovakia

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In this study, we have investigated the microstructure and magnetic entropy change of annealed LaFe11.0Co0.8(Si0.4Al0.6)1.2 alloy in a form: of bulk samples and melt-spun ribbons. The bulk samples were annealed at 1323 K for 20 and 49 days and the maximum values of the magnetic entropy change | Δ SM | obtained after the change of external magnetic field from 0 to 5 T reached 7.5 J kg-1 K-1 and 7.7 J kg-1 K-1, respectively. For the melt-spun ribbon annealed at the same temperature for 1 h, the maximum value of | Δ SM | reaches 4.5 J kg-1 K-1. The temperature corresponding to the maximum entropy change increased from 292 K for bulk samples to 295 K for melt-spun ribbons. The lower values of the magnetic entropy change in the melt-spun LaFe11.0Co0.8(Si0.4Al0.6)1.2 are attributed to the presence of higher volume fraction of the secondary bcc-Fe phase in the ribbon samples.

DOI: 10.12693/APhysPolA.118.910 PACS numbers: 75.30.Sg, 75.50.Bb