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Influence of Mn on the magnetocaloric effect in Nanoperm-type alloys

Rafael Caballero-Flores 1Victorino Franco 1Alejandro Conde 1Laszlo F. Kiss 2

1. Universidad de Sevilla (USE), Sevilla 41012, Spain
2. Hungarian Academy of Sciences, Research Institute for Solid State Physics and Optics (SZFKI), Konkoly Thege M. út 29-33, Budapest H-1121, Hungary


Magnetic refrigeration is currently gaining an increasing interest due to the discovery of materials with remarkable magnetocaloric response close to room temperature. Among others, the main advantages of the refrigerators based on the magnetocaloric effect (MCE) with respect to the systems based on the compression-expansion gas cycle are an improvement in the energetic efficiency and the avoidance of ozone depleting and green-house effect gasses. The characterization of the magnetocaloric materials is based on two parameters: the peak of the magnetic entropy change (ΔSMpk) and the refrigerant capacity (RC). The study of amorphous materials for use in magnetic refrigeration has been motivated by finding a compromise between the aforementioned parameters: a modest ΔSMpk with a high RC. These quantities together with their reduced magnetic and thermal hysteresis, high electrical resistivity, acceptable mechanical properties and corrosion resistance make them good candidates as magnetic refrigerators. The aim of this work is to study the influence of the manganese content on the magnetocaloric response of the Fe80-xMnxB20 alloy series (x = 10, 15, 18, 20 and 24). The magnetic entropy change has been calculated from the numerical derivative of the magnetization curves with respect to temperature and subsequent integration in field, and the RC have been obtained from the product of ΔSMpk times the full temperature width at half maximum of the peak (RCFWHM). The results indicate a nearly linear dependence on the manganese content of the Curie temperature Tc, the maximum magnetic entropy change ΔSMpk, and the magnetic refrigeration RCFWHM, with slopes of -20 K/at. % Mn, -0.04 J·K-1·kg-1/at. % Mn and ‑3.5 J·kg‑1/at. % Mn, respectively.


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Presentation: Poster at E-MRS Fall Meeting 2009, Symposium H, by Rafael Caballero-Flores
See On-line Journal of E-MRS Fall Meeting 2009

Submitted: 2009-05-25 13:53
Revised:   2009-06-07 00:48