Optimization of La(Fe,Co)13−xSix based compounds for magnetic refrigeration

• Published in: Journal of physics. Condensed matter Vol. 19; no. 23; pp. 236230 - 236230 (7)
• Main Authors: Balli, M, Fruchart, D, Gignoux, D
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 13.06.2007; Institute of Physics
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Magnetic properties and materials; Magnetically ordered materials: other intrinsic properties; Magnetocaloric effect, magnetic cooling; Physics; Lanthanum alloys; Curie point; Magnetization; Magnetic field effects; Entropy; Iron alloys; XRD; Magnetic transitions; Optimization; Magnetic refrigerators; Silicon alloys; Magnetocaloric effects; Chemical composition; Cobalt alloys; Transition element alloys
• ISSN: 0953-8984; 1361-648X
• DOI: 10.1088/0953-8984/19/23/236230

The effect of Co on the magnetic, structural and magnetocaloric properties of the LaFe11.7-xCoxSi1.3 (x = ,0.,0.,0.,0.6) and LaFe11.2-xCo0.7+xSi1.1 (x = ,0.,0.2) compounds was investigated by x-ray diffraction and magnetic measurements. For LaFe11.7-xCoxSi1.3 series, the Curie temperature TC increases with increasing Co content. By varying x up to 0.6, the TC of LaFe11.7-xCoxSi1.3 alloys increases from 190 to 265 K and the peak of the isothermal entropy change -DeltaSmax decreases from 28 to 15 J kg-1 K-1 under 5 T. Meanwhile, with Co concentration increasing from 0 to 0.2 in LaFe11.2-xCo0.7+xSi1.1 formula, TC passes from 270 to 294 K and -DeltaSmax decreases from 16.5 to 13.5 J kg-1 K-1 under 5 T. Besides, for magnetic refrigeration systems using the Ericsson cycle, the entropy change must remain constant over the refrigeration range. So, we selected some alloys based on LaFe11.7-xCoxSi1.3 (x = 0.,0.,0.6) and LaFe11.2-xCo0.7+xSi1.1 (x = 0.1 and 0.2) compounds in order to form a composite material working in the 240-300 K temperature range. The optimal mass ratios of the constituents versus magnetic field were calculated. The obtained entropy change of the composite remains approximately constant within the temperature range 240-300 K.