Enhancement of ferromagnetism by Cr doping in Ni-Mn-Cr-Sb Heusler alloys

Abstract

A series of Mn rich Ni50Mn37−xCrxSb13 Heusler alloys have been investigated by dc magnetization and electrical resistivity measurements. Due to the weakening of the Ni-Mn hybridization, the martensitic transition shifts to lower temperatures with increasing Cr concentration, while the saturation magnetization at 5 K increases. The magnetoresistance and exchange bias properties are dramatically suppressed with increasing Cr concentration. The observed behaviors suggest that substitution of Cr for Mn in Ni50Mn37−xCrxSb13 Heusler alloys not only destabilizes the martensitic phase but also enhances ferromagnetism in the system. The possible mechanisms responsible for the observed behavior are discussed.

Tuning martensitic transformation, large magnetoresistance and strain in Ni 50−x Fe x Mn 36 Sn 14 Heusler alloys

“…Such a suppression results in the stabilization of the austenite phase, and it in turn gives rise to the shift of M s towards lower temperature [26]. In addition, with the increase of Fe concentration, the distance of Ni-Mn will increase as the radius of Fe is larger than that of Ni, the hybridization between Ni 3d e g states and the 3d states of the excess Mn atoms at the Sn sites becomes weaker, leading to the shift of M s to the lower temperature [17,27].…”

“…The magnetic properties can be mainly attributed to the Mn magnetic moments since Ni atoms have a small or negligible moment. Thus, the complex properties of Mn rich Heusler alloys not only depend on the martensitic phase transition but also depend strongly on the magnetic transition [17].…”

Martensitic phase transformations and magnetocaloric effect in Al co-sputtered Ni–Mn–Sb alloy thin films

“…3. In Mn rich Ni-Mn based alloys, the change in magnetization at T M is attributed to the suppression of the antiferromagnetic (AFM) interactions of the martensitic phase during the phase transition [36]. The thermal hysteresis width ( T) of phase transformation changes with increase of Al concentration for different samples as shown in Table 1.…”

“…The partial substitution of Al for Mn influences the strength of the Ni-Mn hybridization of Ni-Mn-Sb-Al alloy thin films. The strength of this hybridization is strongly influenced by the Ni-Mn distance [32,[36][37][38]. Therefore, Al addition affects the Ni-Mn distance in Ni-Mn-Sb-Al alloy thin films, and it gets smaller as compared to pure Ni-Mn-Sb film.…”

Ab initiocalculations of structural and magnetic properties of Ni-Co-Mn-Cr-Sn alloys

“…The idea of these investigations is that the addition of Cr lead to decreasing of magnetic moment at martensitic state. In this case the large difference between magnetization in austenite and martensite is observed, which lead to the large value of magnetocaloric effect [3,4]. In [5][6][7] structural and magnetic properties of Ni-Co-Mn-Cr-In alloys with the help of first principles and Monte-Carlo simulations were investigated.…”