摘要:
本文研究了4d过渡族金属Zr取代(Mn,Fe)2 (P,Si)合金中Fe原子对其晶体结构、居里温度、热滞以及磁热性能的影响规律。结果显示,当Zr取代10at.%的Fe时,可将MnFeP0.65Si0.35原始样品的热滞由18 K降低至1.5K,大大提高其相变的可逆性。然而,当Zr原子的含量增加至20 at.%时,热滞出现了上升,这主要由于过量的Zr造成了Mn5Si3型第二相的出现,消耗了主相中的部分Si原子所致。与此同时,随着Zr含量的增加,居里温度逐渐上升。这是由于Zr取代部分Fe原子削弱了(Mn,Fe)2 (P,Si)合金中Fe-Si的化学键合作用,增强了铁磁相的稳定性,从而提高了该合金的居里温度。此外,Zr掺杂的(Mn,Fe)2 (P,Si)合金仍然表现出较强的磁热性能。因此,Zr掺杂的(Mn,Fe)2 (P,Si)合金因其具有较小的热滞、可调的居里温度以及优异的磁热性能有望应用于室温磁制冷和能量转换领域。 Theinfluence of 4d transition metal Zr substitution on the structure,magnetoelastic transition and magnetocaloric properties has been investigatedfor the MnFe1-xZrxP0.65Si0.35alloys. The substitution for Fe by 10 at.% Zr significantly diminishes the thermalhysteresis (ΔThvs) from 18 to 1.5 K and hence greatlyenhances the reversibility of the magnetoelastic transition. However, a furtherincrease in the Zr content to 20 at.% deteriorates the thermal hysteresis. Thisis due to the formation of Mn5 Si3-type impurity phase, which depletes the Si atoms in the main phase. The Curietemperature (TC) is raised with the increasing Zrcontent. This is due to the Zr-induced weakening of the Fe-Si covalent bonding,which stabilizes the ferromagnetic state and thus increases the TC.Additionally, the giant magnetocaloric effect (MCE) is retained in theZr-substituted samples. Consequently, the combination of small ΔThvs,tunable TC and giant MCE has made the Zr-substituted (Mn,Fe)2 (P,Si) promising for room-temperature magnetic refrigerationand energy conversion applications.