The Effect of Different Atomic Substitution at Mn Site on Magnetocaloric Effect in Ni50Mn35Co2Sn13 Alloy

Chengfen Xing,Yaning Xiao,Hu Zhang,Xingyu Liu,Yingli Zhang,Dai He,Zhijie Qiu,Kewen Long,Yi Long,Hanning Zhang

doi:10.3390/cryst8080329

Chengfen Xing, Yaning Xiao + Show 8 more

Open Access

https://doi.org/10.3390/cryst8080329

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Abstract

The effect of different atomic substitutions at Mn sites on the magnetic and magnetocaloric properties in Ni50Mn35Co2Sn13 alloy has been studied in detail. The substitution of Ni or Co for Mn atoms might lower the Mn content at Sn sites, which would reduce the d-d hybridization between Ni 3d eg states and the 3d states of excess Mn atoms at Sn sites, thus leading to the decrease of martensitic transformation temperature TM in Ni51Mn34Co2Sn13 and Ni50Mn34Co3Sn13 alloys. On the other hand, the substitution of Sn for Mn atoms in Ni50Mn34Co2Sn14 would enhance the p-d covalent hybridization between the main group element (Sn) and the transition metal element (Mn or Ni) due to the increase of Sn content, thus also reducing the TM by stabilizing the parent phase. Due to the reduction of TM, a magnetostructural martensitic transition from FM austenite to weak-magnetic martensite is realized in Ni51Mn34Co2Sn13 and Ni50Mn34Co2Sn14, resulting in a large magnetocaloric effect around room temperature. For a low field change of 3 T, the maximum ∆SM reaches as high as 30.9 J/kg K for Ni50Mn34Co2Sn14. A linear dependence of ΔSM upon μ0H has been found in Ni50Mn34Co2Sn14, and the origin of this linear relationship has been discussed by numerical analysis of Maxwell’s relation.

Highlights

Over the past decades, Ni-Mn-Z (Z = Ga, In, Sn, and Sb) Heusler alloys have attracted significant attention due to its noteworthy multifunction properties, such as magnetic shape memory effect [1], magnetoresistance [2,3], exchange bias (EB) [4], and magnetocaloric effect (MCE) [5,6]
Similar results have been reported in other Heusler alloys [14,15], e.g., the substitution of Co for Ni modifies the magnetic structure of the austenite into FM as the preferred state and reduces the martensitic transformation temperature [15]
We systematically study the effect of substituting Ni, Co, and Sn for Mn atoms for the magnetic and magnetocaloric properties in

Summary

Introduction

As one of the typical Ni-Mn-Z Heusler alloys, Ni-Mn-Sn alloy undergoes a martensitic transformation from ferromagnetic (FM) austenite to weak-magnetic martensite, which is accompanied with an abrupt change of magnetization ∆M [6]. Sn sites (4b positions), and are coupled antiferromagnetically (AFM) to the surrounding Mn atoms on the regular Mn site (4a positions) [11,12] This fact suggests that excess Mn would lead to the weakness of ∆M during the martensitic transformation. Similar results have been reported in other Heusler alloys [14,15], e.g., the substitution of Co for Ni modifies the magnetic structure of the austenite into FM as the preferred state and reduces the martensitic transformation temperature [15]. Different atomic substitutions at Mn sites have different effects on the martensitic transformation and the MCE.

Experimental

35 Sn213Sn

Magnetization isothermsofofNi-Mn-Co-Sn

The and280

Conclusions