Ferromagnetism and antiferromagnetism in Ni2+x+yMn1−xAl1−y alloys

Structural-induced antiferromagnetism in Mn-based full Heusler alloys: The case of Ni2MnAl

“…The Néel temperature for the AFM B2 phase was found to be 313 K and the Curie temperature for the FM L2 1 phase 375 K. Similar results were also produced by Dong et al in the case of thin films of Ni 2 MnAl grown on GaAs͑001͒ using molecular beam epitaxy and no sole L2 1 phase could be produced. 16 The competition between the FM and AFM ordering has been also observed on films by Paduani et al 17 A mixed Ni 2 Mn͑Ga x Al 1−x ͒ alloy has been also proposed as an intermediate way to combine the mechanical properties of Ni 2 MnAl and the easily achieved ordering of the L2 1 structure in Ni 2 MnGa which is essential for the martensitic transition to occur. 18 The mixed B2 / L2 1 of Ni 2 MnAl has been used to produce negative magnetoresistance ratio in granular films.…”

Investigation of ferromagnetism in Mn1−xAl1−yFex+y alloys

“…12.5 Mn 42.5 Al 45.0 , and the saturation magnetization is 380 G/cc and 400 G/cc, respectively, in a field of 15 kOe. The origin of the ferromagnetism in these alloys has been ascribed to the FM exchanges between Mn atoms, unlike the observed behavior in other MnAl-based [6][7][8][9]. Since the physical properties of these materials are strongly dependent upon composition, in this contribution we investigate effects of the iron content on the magnetic properties of the Mn 1−x Al 1−y Fe x+y compounds.…”

Exchange-bias via nanosegregation in novel Fe2−xMn1+xAl (x = −0.25, 0, 0.25) Heusler films

“…43,62 This splitting is incompatible with a collinear homogeneous antiferromagnetic state, and has been attributed to pinning of ferromagnetic moments via antiferromagnetic anisotropy. 43,62,63 This suggestion implies that the L2 1 -B2 mixed state is heterogeneous, with separated ferromagnetic and antiferromagnetic regions. However, in the absence of direct observations, the microstructure of the mixed L2 1 -B2 Heusler state has remained so far elusive.…”