Adiabatic magnetocaloric effect in Ni50Mn35In15 ribbons

Abstract

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, the material should have a high surface/volume ratio. In this work, the typical Ni50Mn35In15 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 thermomagnetization measurements. The inverse and conventional magnetocaloric effects (MCEs) associated with the martensitic transformation (MT) and the ferromagnetic transition of the austenite (TCA), respectively, were measured directly by the adiabatic method (ΔTad) and indirectly by estimating the magnetic entropy change from magnetization 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 MT temperature of 300 K for inverse MCE, and ΔTad = 2.3 K for conventional MCE at TCA = 309 K. This result strongly motivates further development of different MetaMSMA refrigerants shaped as ribbons.

Effect of solidification rate on martensitic transformation behavior and adiabatic magnetocaloric effect of Ni50Mn35In15 ribbons

“…MC effect has been studied in MetaMSMA melt-spun ribbons by assessing SM [22], or Tad values from heat capacity dependences under magnetic field (see, e.g., [23]). Whereas there exists a number of reports on the direct measurements of ∆Tad in the bulk MetaMSMAs [20,[24][25][26], the Tad data for MetaMSMAs ribbons are scarce due to the experimental difficulty to measure the adiabatic temperature change in ribbons [27,28].…”

Inverse magnetocaloric effects in metamagnetic Ni-Mn-In-based alloys in high magnetic fields

“…The results in Ref. [4] were obtained on samples quenched in water from 800 o C. Plastic deformations of the alloys can also lead to changes in the MST temperatures and MCE values in Heusler alloys [15]. As mentioned earlier, ΔS t shows the same tendency (see Table 1).…”

Magnetocaloric effect in W-doped Ni–Mn–Sn alloy probed by direct and indirect measurements

“…During cooling from 350 K, the paramagnetic austenite becomes first ferromagnetic at the Curie temperature, T C A [14] and secondly then, during subsequent cooling, exhibits a sharp drop of magnetization, which is associated with MT from the ferromagnetic austenite state to a weakly magnetic martensite. After further cooling, magnetic ordering of the martensite phase reinforces at T C M , what is particularly evident in the W1Sn sample [43,44]. This behavior in Ni-Mn-based Heusler-type metaMSMAs was interpreted as a result of the strengthening of ferromagnetic correlations in the martensite phase [45].…”