Pressure tuning reverse martensitic transformation in the MnCoNiGe half-Heusler alloy.

Here we investigate the structural properties of the MnCoNiGe half-Heusler alloys under pressure up to 12 GPa by Synchrotron angle-dispersive x-ray diffraction (XRD). At room temperature and pressure, the compound exhibits only the hexagonal NiIn-type structure. Lowering the temperature to 100 K at ambient pressure induces an almost complete martensitic phase transformation to the orthorhombic TiNiSi-type structure.