Dynamical Effects of the Martensitic Transition in Magnetocaloric Heusler Alloys from Direct<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi mathvariant="normal">Δ</mml:mi><mml:msub><mml:mi>T</mml:mi><mml:mi>ad</mml:mi></mml:msub></mml:math>Measurements under Different Magnetic-Field-Sweep Rates

Abstract

Solid-state magnetic refrigeration could disrupt conventional technology based on gas compressors, but affordable materials with large magnetocaloric response are needed. Using direct measurements of adiabatic temperature change in three different regimes of magnetic-field sweep rate, the authors investigate the dynamics of the martensitic transition in a class of Heusler alloys. Here phase-boundary motion is not an issue, but the speed of nucleation can be a limiting factor at high sweep rates. For everyday devices working at around 10 Hz, though, these compounds are promising.