Martensitic transition and structural modulations in the Heusler alloy Ni2FeGa

Abstract

We have found two distinctive structural modulations altering evidently along with the martensitic transition (MT) in the Ni 2 FeGa alloy. The first one ðq 1 Þ; corresponding to the well-known phonon anomalies in the ½zz0 TA 2 branch, occurs along the k110l direction. The second one ðq 2 Þ; an incommensurate modulation observed for the first time, occurs along the k211l-direction. Both modulations change gradually with the premartensitic phonon softening and discontinuously with the MT. Anomalies in magnetic properties emerging around the MT have been briefly discussed. q

Elastocaloric effect in Ni50Fe19Ga27Co4 single crystals

“…It is worthy to note that two sets of satellite reflections are visible around each fundamental Bragg spot. They are considered to be caused by the structural modulation, which was also reported in the Ni 2 FeGa alloys [22,23]. However, the modulated structure was not detected by XRD measurement.…”

Microstructure and low-temperature phase transition in Ni2FeGa Heusler alloy

“…and magnetic-field-induced strain, etc., have been extensively discussed [11][12][13][14][15][16][17]. It is also noted that numerous types of superstructure modulations appear along with martensitic transition at low temperatures [18,19]. For Ni 2 FeGa, it is found that, with increasing Ni concentration in ribbons, the martensitic transformation temperature increases progressively, on the other hand, the Curie temperature decreases from 440 to 312 K [3].…”

Magnetic properties of ferromagnetic shape memory alloys Ni2Mn1 − Fe Ga

“…Recently new promising FSMAs have been found in Fe-Ni-Ga alloys [10][11][12][13]. These alloys are characterized by a wide range of T M from ∼150 to ∼300 K and excellent ductility.…”