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An inverse magnetocaloric effect is studied in Ni2Mn1+xX1-x-type Heusler alloys. Principally known for their shape-memory properties, these alloys also exhibit significant entropy and temperature changes (ΔS and ΔTAd, respectively) under adiabatic conditions when a modest magnetic field is applied. We investigated the impact on magnetocaloric properties of introducing substantial chemical disorder on the X-site (X = Si, Ga, In), of replacing Ni with nonmagnetic Ag, and of replacing a small amount of Mn with Gd. While a reduction in ΔS is observed in the first two cases, we observe a significant enhancement of ΔS when a small amount of Gd is substituted for Mn. A thermodynamic analysis was conducted using magnetization and heat capacity data to estimate adiabatic temperature changes in the range of ΔTAd ≃ -1 to -3 K for a 5 T magnetic field. Several alloys characterized in this study exhibit these respectable ΔTAd values near room temperature, making them potentially viable candidates for magnetic refrigeration applications.
White, B. D., Barabash, R. I., Barabash, O. M., Jeon, I., & Maple, M. B. (2019). Magnetocaloric effect near room temperature in quintenary and sextenary Heusler alloys. Journal of Applied Physics, 126(16), 165101. https://doi.org/10.1063/1.5120819
Journal of Applied Physics
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