Speaker
Description
The Ni 1.92 Mn 1.56 Sn 0.52 belongs to a family of Heusler alloys with peculiar magnetic, structural
and transport properties that can be potentially useful for applications. They show structural
transition from high temperature cubic austenite (A) to low temperature orthorhombic
martensite (M) with significant changes of volume, magnetization, resistivity and Hall effect.
We have performed study of temperature dependence of electrical resistivity, Hall coefficient
and heat conductivity of Ni 1.92 Mn 1.56 Sn 0.52 in temperature region between 4 K and 400 K. The
ferromagnetic ordering accompanied by sharp change of resistivity T-derivative was
established below T C = 320 K. Structural A-M transition at cooling, T A-M = 282 K, induces a
large increase of resistivity and vice versa, M-A transition at heating, T M-A = 294 K, induces a
decrease of resistivity. It is worth to note that A-M transition is associated with transition
from ferromagnetic austenite to martensite with almost zero magnetization. The re-entrance of
magnetization at T c = 235 K is accompanied with any resistivity anomaly. The maximum of
resistivity around 150 K is followed by a shallow T 2 resistivity dependence. An unusual
character of temperature dependence of the Hall effect points to dramatic changes in
electronic structure during the structural transition.
