Phase transitions and thermal expansion in Ni$_{51-x}$Mn$_{36+x}$Sn$_{13}$ alloys

Thermal expansion and structural and magnetic phase transitions in alloys of the Ni–Mn–Sn system have been investigated. The spontaneous martensitic transformation in Ni$_{51-x}$Mn$_{36+x}$Sn$_{13}$ (0 $\le x\le$ 3) alloys is found to be accompanied by high jumps in the temperature dependences of the linear thermal expansion. The relative change in the linear sizes of these alloys at the martensitic transformation is $\sim$1.5 $\cdot$ 10$^{-3}$. There are no anomalies in the magnetic-ordering temperature range in the temperature dependences of the coefficient of linear thermal expansion. The differences in the behavior of linear thermal expansion at the martensitic transformation in Ni$_{51-x}$Mn$_{36+x}$Sn$_{13}$ (0 $\le x\le$ 3) and Ni$_{47}$Mn$_{40}$Sn$_{13}$ ($x$ = 4) alloys have been established.