Standard enthalpies of formation of selected Ru2YZ Heusler compounds

Abstract

The standard enthalpies of formation of selected ternary Ru-based Heusler compounds Ru2YZ (Y=Fe, Hf, Mn, Ti, V; Z=Al, Ga, In, Si, Ge, Sn) were measured using high temperature direct reaction calorimetry. The measured enthalpies of formation (in kJ/mole of atoms) of the Heusler compounds are, Ru2FeGe (−19.7±3.3); Ru2HfSn (−24.9±3.6); Ru2MnSi (−46.0±2.6); Ru2MnGe (−29.7±1.0); Ru2MnSn (−20.6±2.4); Ru2TiSi (−94.9±4.0); Ru2TiGe (−79.1±3.2); Ru2TiSn (−60.6±1.8); Ru2VSi (−55.9±1.7);for the B2-structured compounds, Ru2FeSi (−28.5±0.8); Ru2HfAl (−70.8±1.9); Ru2MnAl (−32.3±1.9); Ru2MnGa (−25.3±3.0); Ru2TiAl (−62.7±3.5); Ru2VAl (−30.9±1.6); Ru2ZrAl (−64.5±1.5). Values were compared with those from published first principles calculations and the OQMD (Open Quantum Materials Database). Lattice parameters of these compounds were determined using X-ray diffraction analysis (XRD). Microstructures were identified using scanning electron microscopy (SEM) and Energy Dispersive Spectroscopy (EDS).