Standard enthalpies of formation of selected Rh2YZ Heusler compounds

Abstract

The standard enthalpies of formation (ΔfH°) of selected ternary Rh-based Rh2YZ (Y=Cu, Fe, Mn, Ni, Ru, Ti, V; Z = Al, Ga, In, Si, Ge, Sn) compounds were measured using high temperature direct reaction calorimetry. The measured standard enthalpies of formation (in kJ/mol of atoms) are, for the Heusler compound Rh2MnSn (−40.1 ± 3.6), for the B2-structured compounds: Rh2FeAl (−48.5 ± 2.9); Rh2MnAl (−72.4 ± 2.7); Rh2MnGa (−55.3 ± 2.0); Rh2MnIn (−35.3 ± 1.9), for the tetragonal compounds: Rh2FeSn (−28.9 ± 1.3); Rh2TiAl (−97.6 ± 2.2); Rh2TiGa (−79.0 ± 1.8); Rh2TiSn (−74.7 ± 3.1). Values are compared with those from first principles calculations in published papers and the Open Quantum Materials Database (OQMD). Lattice parameters of these compounds are determined using X-ray diffraction analysis (XRD). Microstructures were characterized using scanning electron microscopy (SEM) and Energy Dispersive Spectroscopy (EDS).