Large recalescence-like event at the first cooling across the magnetic transition of (Mn,Fe)2(P,Si) magnetocaloric materials

Abstract An unconventional phenomena is observed at the first-order magnetic transitions in (Mn,Fe) 2 (P,Si) materials. Here, we show that the first crossing of the transition upon cooling is associated with an abnormal temperature increase. While differential scanning calorimetry can detect this recalescence-like event, purposely-designed probes were employed to quantify it. Recalescence at a magnetic transition is extremely rare. But in (Mn,Fe) 2 (P,Si), it is even more remarkable by its amplitude, with the temperature rising up to +4.0 K. In (Mn,Fe) 2 (P,Si), this phenomenon is associated with irreversible burst-like evolution of the microstructure (increase in defect concentration and micro-cracking) and of the crystal structure.