First-Principles study of Ni-In intermetallic phases: cohesive, electronic, magnetic, thermodynamic, and mechanical properties

C. DELUQUE TORO; S.B. RAMOS; A.M. MONTI

San Carlos de Bariloche

Simposio; Simposio Latinoamericano de Física del Estado Sólido (SLAFES) XXIII; 2018

Centro Atómico Bariloche

The possibilities of Ni as contact material inelectronic applications has motivated the interest on the intermetallic phasesof the Ni-In system in relation to the In-Sn alloys and their use in lead freemicro-soldering processes. In spite of this, the available literature aboutcohesive, electronic and magnetic properties of the Ni-In system is scarce. Atheoretical study of such properties specifically for the compounds Ni3In-hP8, Ni2In-hP6, NiIn-hP6 and Ni2In3-hP5, was previously carried out by the authors. The present work complements such studyby including two additional phases, i.e., Ni3In-cP4 and NiIn-cP2,which compete in stability with Ni3In-hP8 and NiIn-hP6,respectively. In particular, we are interested in the analysis of the relativestability between Ni3In-hP8 and Ni3In-cP4 phases, noticing that previous ab initio calculations conduct to conclusions different from the ones presented in this work. To investigate this issue we perform calculations using the Full Potential Linearized Augmented Plane Waves(FP-LAPW) method, within the framework of the Density Functional Theory (DFT)and both Generalized Gradient (GGA) and Local Density (LDA) approximations. Structural parameters, formation energies and cohesive properties of thestudied phases and its constituent elements were obtained through minimizationof the unit cell parameters. For the Ni3In-hP8 and Ni3In-cP4 phases, we also calculate their elastic constants, and based on the averaged elastic moduli, we present some predictions concerning the mechanical properties of these phases and the thermodynamic properties were calculated from the equation of state using the quasi-harmonic model of Debye. Finally, the electronic characteristics of several Ni-In compounds are compared throughthe density of states (DOS) of each optimized structure revealing that only Ni3In-hP8 and Ni3In-cP4 are ferromagnetic phases.