REPETITIVE PHASE TRANSITION MEASUREMENTS IN Ni₅₀Mn₂₆Ga₂₄

Andrea Chudiková – Tomáš Ryba – Zuzana Vargová – Sergej Ilkovič
– Marián Reiffers– Vladimír Komanický – Róbert Gyepes – Rastislav Varga

   We have performed basic characterization of rapidly quenched Ni₅₀Mn₂₆Ga₂₄ Heusler ribbon. It is characterized by austenitic phase Fm-3m in B2 modification at room temperature and by structural transition to martensitic phase around 200 K. Rapid quenching results in the metastable state that is demonstrated by the variation of four characteristic transition temperatures As, Af, Ms and Mf. However after 6th training cycle, the transition temperatures and hysteresis becomes stable. This proves, that rapid quenching can be potentially interesting method of production of Heusler alloys that could be suitable for practical magnetocaloric application.

Keywords: Heusler alloys, magnetocaloric effect, resistance dependence on temperature

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