The inverse magnetocaloric effect in Ni-Mn based Heusler compounds occurs during the magnetostructural transition between low-temperature, low-magnetization martensite and high-temperature, high-magnetization austenite. In this study, we analyze the metamagnetic transformation of a ${\mathrm{Ni}}_{49.8}{\mathrm{Mn}}_{35}{\mathrm{In}}_{15.2}$ compound by simultaneous adiabatic temperature change $\mathrm{\Delta }{T}_{ad}$ and strain $\mathrm{\Delta }l/l_0$ measurements in pulsed magnetic fields up to 10 T. We observe a $\mathrm{\Delta }{T}_{ad}$ of −10 K and a $\mathrm{\Delta }l/l_0$ of −0.22% when the reverse martensitic transition is fully induced at a starting temperature of 285 K. By a variation of the magnetic field-sweep rates between 316, 865, and $1850\mathrm{T}{\mathrm{s}}^{-1}$, the transitional dynamics of the reverse martensitic transformation have been investigated. Our experiments reveal an apparent delay upon the end of the reverse martensitic transformation at field rates exceeding $865\mathrm{T}{\mathrm{s}}^{-1}$ which is related to the annihilation of retained martensite. As a consequence, the field hysteresis increases and higher fields are required to saturate the transition. In contrast, no time-dependent effects on the onset of the reverse martensitic transformation were observed in the studied field-sweep range. Our results demonstrate that kinetic effects in Heusler compounds strongly affect the magnetic cooling cycle, especially when utilizing a multicaloric “exploiting-hysteresis cycle” where high magnetic field-sweep rates are employed.

• Received 4 May 2020
• Revised 9 October 2020
• Accepted 3 November 2020

DOI:https://doi.org/10.1103/PhysRevMaterials.4.111401