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

摘要

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.