Computational and experimental study of phase stability, cohesive properties, magnetism and electronic structure of TiMn2

By an ab initio approach we calculated phase stability, cohesive and magnetic properties, and the electronic structure of TiMn2 for the C14 and C15 Laves structure types. The nonmagnetic C14 phase is the ground state in accordance to experiment, whereas a metastable ferromagnetic C15 phase is predicted with a local magnetic moment of 0.78 œß for Mn. The energy of formation was measured by a calorimetric drop experiment resulting in a value of -86.76‘6.79 kJ mol-1 at 298 K being in good agreement to the ab initio result of -88.8 kJ mol-1. Model calculations based on Miedema's approach failed to yield reasonable results. The calculated densities of states reveal strong hybridisation between Ti-like and Mn d-like states. Œ 2003 Acta Materialia Inc. Published by Elsevier Science Ltd. All rights reserved.