Adiabatic magnetocaloric effect in Ni50Mn35In15 ribbons

Heusler-type Ni-Mn-based metamagnetic shape memory alloys (MetaMSMAs) are promising candidates for magnetic refrigeration. To increase heat exchange rate and efficiency of cooling, thematerial should have a high surface/volume ratio. In this work, the typicalNi50Mn35In15 MetaMSMA was selected to fabricate thin ribbons by melt-spinning. The characteristic transformations of the ribbons were determined by calorimetry, X-ray diffraction, scanning electron microscopy and thermomagnetizationmeasurements. The inverse and conventional magnetocaloric effects(MCEs) associated with the martensitic transformation (MT) and theferromagnetictransition of the austenite (TCA), respectively, weremeasured directly by the adiabatic method ( ΔTad) and indirectly by estimating the magneticentropy change frommagnetization measurements. It is found that the ribbons exhibit large values of ΔTad = −1.1 K at μ0ΔH = 1.9 T, in the vicinity of the MTtemperature of 300  K for inverseMCE, and ΔTad = 2.3 K for conventionalMCE atTCA  =  309 K. This result strongly motivates further development of different MetaMSMA refrigerants shaped as ribbons.

Source: Applied Physics Letters - November 22, 2016 Category: Physics Authors: P. Álvarez-Alonso, C. O. Aguilar-Ortiz, J. P. Camarillo, D. Salazar, H. Flores-Zúñiga and V. A. Chernenko Source Type: research