The effect of metal/non-metal ratio on the microstructure and magnetic properties of (MnFe)x(P0.5Si0.5) microwires.

The effects of metal/non-metal ratio (M/NM ​= ​ x : 1) on the microstructure and magnetocaloric properties of promising melt-extracted Mn–Fe–P–Si microwires with short heat treatment have been investigated here. More Fe 2 P principal phase, which is considered favorite for magnetocaloric effect (MCE), should achieve at low M/NM ratio and the fraction of Fe 2 P phase increased with the reduction of x. Meanwhile, the (Mn, Fe) 3 Si impurity phase is formed for x ​= ​2.00–1.90 whereas change to (Mn, Fe) 5 Si 3 structure for x ​= ​1.85. It's worth noting that a metal deficiency resulted in the thermal hysteresis (T hys) and the magnetic hysteresis loss (W y) decreased by ∼40 ​%., The magnetic transition temperature (T tran), peak value of isothermal magnetic entropy change (− Δ S iso peak), refrigerant capacity (RC) and effective refrigerant capacity (RCE) first increased then decreased with the decrease of x , and reached the maximums at x ​= ​1.90, i.e., 370 ​K, 26.0 ​J ​kg−1 ​K−1, 367.4 and 339.8 ​J ​kg−1, respectively. Therefore, the customizable microstructure and magnetic properties of the melt-extracted (MnFe) x (P 0.5 Si 0.5) microwires will be achievable effectively by tuning M/NM ratio x , and optimized Mn–Fe–P–Si compounds with novel thermomagnetic properties will be obtained. [Display omitted] • The (MnFe) x (P 0.5 Si 0.5) microwires were fabricated by melt-extracted method. • The high amount of Fe 2 P phase would be obtained by reducing the M/NM. • The ​− ​ Δ S iso peak is −26.0 ​J ​kg−1 ​K−1 (5 ​T) for the wires with x ​= ​1.90. [ABSTRACT FROM AUTHOR]