Method of making active magnetic refrigerant materials based on Gd-Si-Ge alloys
AssigneeIowa State University Research Foundation, Inc.
InventorsAlexandra O. Pecharsky, Karl A. Gschneidner, Jr., Vitalij K. Pecharsky
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Abstract
An alloy made of heat treated material represented by Gd5(SixGe1−x)4 where 0.47≦x≦0.56 that exhibits a magnetic entropy change (−ΔSm) of at least 16 J/kg K, a magnetostriction of at least 2000 parts per million, and a magnetoresistance of at least 5 percent at a temperature of about 300K and below, and method of heat treating the material between 800 to 1600 degrees C. for a time to this end.
Claims8
Heat treated material comprising Gd5(SixGe1−x)4 where 0.47≦x≦0.56, said material exhibiting in an annealed condition a magnetic entropy change (−ΔSm) that is higher than that exhibited when in the as-solidified, unheat treated condition for a magnetic field change of 0 to 50 kOe at a temperature of about 300K and below.
Heat treated material comprising R5(SixGe1−x)4 where 0≦x≦1.0 and R is one or more rare earth elements other than Gd, said material exhibiting in an annealed condition a magnetic entropy change (−ΔSm) that is higher than that exhibited when in the as-solidified, unheat treated condition for a magnetic field change of 0 to 50 kOe at a temperature of about 300K and below.
Heat treated material comprising (R1−yR′y)5(SixGe1−x)4 where 0≦y≦1.0and 0≦x≦1.0 and where R and R′ each is a rare earth element and at least one of R and R′ is other than Gd, said material exhibiting in an annealed condition a magnetic entropy change (−ΔSm) that is higher than that exhibited when in the as-solidified, unheat treated condition for a magnetic field change of 0 to 50 kOe at a temperature of about 300K and below.
Dependencies are inferred from the claim text.