Martensitic transition and structural modulations in Ni51Fe24Ga25 ferromagnetic shape-memory alloy

Long- and short-range order in the Ni52Co2Fe20Ga26 ferromagnetic Heusler alloy

“…The value of 2.865 Å found by the fit for this distance corresponds to a lattice constant a = 5.73 Å , shortened by about 0.04 Å with respect to that of the austenitic phase in the reference Ni 54 Fe 19 Ga 27 alloy (Brown et al, 2007). Similar values of the L2 1 lattice constant were found for Ni 51 Fe 22 Ga 27 , Ni 51 Fe 24 Ga 25 (Du et al, 2011) One can see a marked increase in the structural disorder beyond the nearest Ni1 neighbors, with almost the same degree of disorder ( 2 ) for the higher neighboring shells. This structural disorder could be responsible for a certain instability of the system, thus favoring its transition to the martensite on a decrease in temperature (Priolkar et al, 2008;Priolkar, 2014).…”

“…structures, but in the latter structure the Fe and Ga atoms occupy specific sites of the Fm3m symmetry (4a and 4b, respectively) in an orderly fashion, whereas in the former structure Fe and Ga are evenly distributed over these sites (Hamilton et al, 2007). The L2 1 structure is well established by electron Oikawa et al, 2005Oikawa et al, , 2007Santamarta et al, 2006;Zhang et al, 2008;Du et al, 2011), neutron (Lá zpita et al, 2013) and X-ray (Liu et al, 2003;Oikawa et al, 2007;Liu et al, 2008) diffraction, by the (hkl) reflections with all indices odd. The RT XRD pattern of the Ga26 alloy, with distinct ( 111), ( 311) and (333) maxima, clearly indicates the presence of the L2 1 austenite.…”

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.…”

First-principles computation of structural, elastic and magnetic properties of Ni2FeGa across the martensitic transformation

“…The Ni 2 FeGa alloy synthesized using a melt-spinning technique contains a well defined L2 1 order at room temperature. The experimental lattice parameter is 5.74Å with a face centred cubic (fcc) unit cell volume of 189Å 3 [25].…”

“…b Ab initio calculations by Entel [27]. c X-ray diffraction (XRD) and Transmission Electron Microscopy (TEM) experiment [25], Single crystal neutron diffraction experiment [28]. d Full-potential linearized-augmented plane-wave method [13].…”