Properties of a Ductile Magnetic Refrigerant
Magnetocaloric measurements are reported for the solution alloy Er0.8Lap0.2. The measurements are part of an ongoing effort to find and characterize magnetic refrigerants for active magnetic regenerative (AMR) refrigerators. The AMR cycle offers high efficiency and a large temperature span when a ferromagnetic refrigerant is used. Most of the intermetallic line compound magnetic refrigerants studied to date are brittle. The Er-La alloys are relatively ductile, even at LN2 temperature. The magnetization of several Er-La alloys were measured; the Er0.8La0.2 composition was selected as the most promising one for magnetocaloric measurements. Measurements of heat capacity and adiabatic temperature change upon magnetization (ΔTS) are reported for applied fields between 0 and 7 Tesla. The addition of lanthanum to erbium does not greatly affect the heat capacity. However, the temperature dependence of ΔTS changes to a steady increase with temperature between 15 K and 45 K, a characteristic excellent for AMR applications.
KeywordsHeat Capacity Curie Point Magnetocaloric Effect Heat Transfer Area Magnetic Refrigerant
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