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Iowa State University and Ames Laboratory researchers have modified the giant Magneto Caloric Effect alloy La-Fe-Si to create new alloys with greatly improved mechanical properties.

Materials with first-order magnetic phase transition (i.e., giant MCE materials) often suffer from high brittleness, making them unsuitable for applications with magnetic field and temperature cyclic variation.  This brittleness leads to decreasing efficiency of cooling (associated with diminishing maximum adiabatic temperature change in the material) and mechanical failure during cycling.  To address these material deficiencies, Iowa State University and Ames Laboratory researchers have developed new La-Fe-SI alloys in which the addition of a fourth element greatly improves the mechanical properties of the alloy for magneto caloric applications.

These new alloys have been demonstrated to have nearly constant maximum adiabatic temperature change from cycle to cycle, dramatically improved mechanical integrity in response to magnet field and temperature cyclic variation, and tunable Curie temperature from 170 K to near room temperature.  The new alloying elements are low cost at very low dosage.

• Improved mechanical integrity resulting in no cracking after repeated magnetic field cycling.

• Curie temperature tunable from 170 K to near room temperature.

• Nearly constant maximum adiabatic temperature change of 8.2 K; low thermal hysteresis.

• Material compatible with manufacturing in buttons, rods, spheres and plates

Magnetocaloric refrigeration