Effect of Ga substitution on structural and magnetic properties of Fe50Mn25Al25-xGax Heusler alloys

Single-domain Fe2CoGa0.5Al0.5 Heusler alloy nanoparticles with enhanced properties

“…The deviation observed in experimental M s as compared to the theoretically obtained M t of the three nanoparticles might be due to the slight variation in elemental compositions or dead layer thicknesses at the surface of the nanoparticles. Prior studies on bulk Fe 2 MnGa 1− x Al x 10 and Fe 50 Mn 25 Ga x Al 25− x 11 alloys also report such variations in M s with Ga/Al content. The minor decrease in the experimental M s as compared to the theoretical M t can be interpreted by the core–shell model, 38 which splits the nanoparticle into a ferromagnetic core and a non-magnetic dead layer of thickness t around it.…”

“…The comparison of the obtained T C with that of similar sized Fe 2 CoGa (1203 K) and Fe 2 CoAl (1225 K) 20 nanoparticles shows an increment in T C on increasing Al content which is a similar trend obtained in bulk Fe 50 Mn 25 Al 25Àx Ga x alloys. 11 This report provides the first account of synthesizing highly ordered quaternary Fe 2 CoGa 0.5 Al 0.5 nanoparticles using template-less chemical technique. The study also provides theoretical support to the results via ab initio calculations and showcases the enhanced properties of the intermediate compound.…”

“…While it is relatively easy to prepare bulk quaternary HA by arc melting, it is extremely difficult to prepare quaternary HA nanoparticles with desired stoichiometry. Thus one can find only a few reports on bulk quaternary Heusler alloys containing s–p elements Ga and Al, say, Cu 50 Mn 25 Ga x Al 25− x (0 ≤ x ≤ 10), 7 Ru 2 VGa x Al 1− x (0 ≤ x ≤ 1), 8 NiMnGa 2− x Al x (0 ≤ x ≤ 2), 9 Fe 2 MnGa 1− x Al x (0 ≤ x ≤ 1), 10 and Fe 50 Mn 25 Ga x Al 25− x (0 ≤ x ≤ 10) 11 etc. alloys in the literature, with none pertaining to investigations on nanoparticles.…”

“…Similar trend was observed in bulk Ru 2 VGa x Al 1− x (0 ≤ x ≤ 1) alloys, 8 NiMnGa 2 –NiMnAl 2 alloys, 9 and Fe 50 Mn 25 Ga x Al 25− x (0 ≤ x ≤ 10) HA. 11 Mishra et al 11 correctly attributed this behavior to the difference in the atomic radii of Ga and Al. Interestingly, the linear increment in a with Ga content follows the relation, a Fe 2 CoGa 0.5 Al 0.5 ≈ ( a Fe 2 CoGa + a Fe 2 CoAl )/2, in line with the Vegard's law.…”

“…The comparison of the obtained T C with that of similar sized Fe 2 CoGa (1203 K) and Fe 2 CoAl (1225 K) 20 nanoparticles shows an increment in T C on increasing Al content which is a similar trend obtained in bulk Fe 50 Mn 25 Al 25− x Ga x alloys. 11…”