Abstract
Quaternary Heusler alloy
Ni
50
Mn
8
Fe
17
Ga
25
ribbons have been prepared by the melt-spun method. The ribbons exhibit large negative magnetoresistance
(
MR
)
{
=
[
R
(
H
)
−
R
(
0
)
]
∕
R
(
0
)
}
over a wide temperature region, particularly in the region during the martensitic phase transformation. The MR decreases significantly after annealing. The large MR is isotropic and is mainly attributed to the local magnetic disorders, magnetic clusters, and heterogeneity. The maximum MR at martensitic transformation may be due to the redistribution of electrons and the increase of phase boundary scattering. This feature adds a useful functionality to the already interesting Heusler alloys.