Magnetocaloric Effect of Amorphous Gd₆₅Fe₁₀Co₁₀Al₁₀X₅ (X = Al, Si, B) Alloys

Abstract

Gd-based amorphous alloys with addition of metals and metalloids are interesting materials from the point of view of magnetic and magnetocaloric properties. Moreover, they usually possess high corrosion resistance and good mechanical properties. A series of Gd 65 Fe 10 Co 10 Al 10 X 5 (X = Al, Si, B) alloys was synthesized by melt-spinning. The amorphous structure of ribbons was confirmed by X-ray diffraction. Calorimetric curves allowed to determine crystallization temperatures, which are in the range of 260°C-303°C. The temperature dependences of the magnetic entropy changes were calculated from series of isothermal magnetization curves using Maxwell relation. Maximum value of the magnetic entropy change for the magnetic field change from 0 to 5 T is 7.1 J kg −1 K −1 for X = B, whereas the related refrigerant capacity (RC) is 748 J kg −1 . For Gd 65 Fe 10 Co 10 Al 15 and Gd 65 Fe 10 Co 10 Al 10 Si 5 alloys, the maximum values of magnetic entropy change reached 6.0 and 5.9 J kg −1 K −1 , while the obtained values for RC parameter were 700 and 698 J kg −1 , respectively.Index Terms-Amorphous magnetic materials, entropy, magnetocaloric effect, refrigerant capacity.

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