A study of the structural phase transformation in the shape memory alloy Co2NbSn

Resistivity, specific heat and magnetization measurements on the shape memory compound Co2NbSn corroborate the presence of ferromagnetic order below 119 K and a structural phase transition at 235 K. High-resolution neutron powder diffraction measurements confirmed that the high-temperature cubic phase has the Heusler L21 structure and established that the low-temperature phase is orthorhombic with space group Pmma. The thermal variation of the specific heat at low temperatures indicates a high density of states consistent with electronic structure calculations and a band Jahn–Teller mechanism for the transformation