On the crystal structure and magnetic properties of the Mn0.94Ti0.06CoGe alloy

Structural and magnetic properties of Mn0.94Ti0.06CoGe have been studied by a combination of bulk magnetisation and neutron diffraction measurements over the temperature range of 5 K–350 K. The crystal structural transition occurs at Tstr (∼235 K) with a change in symmetry from the low temperature orthorhombic TiNiSi-type structure (space group Pnma) to the high temperature hexagonal Ni2In-type structure (space group P63/mmc) and the magnetic phase transition takes place around TC = 270 K. It is found that the structural transition around Tstr is incomplete and there is a co-existence of the orthorhombic and hexagonal structures between Tstr and TC (∼270 K). These results are discussed in connection with the magnetic and magnetocaloric behaviours in Mn0.94Ti0.06CoGe.